Overload protection mecanism

ABSTRACT

According to the invention, an assembly includes at least one piston assembly ( 4105 ), a rotating member ( 4130 ), and a transition arm ( 4110 ). The transition arm couples the piston assembly ( 4105 ) to the rotating member ( 4130 ). The assembly includes an overload protection mechanism ( 4135 ) coupled to the transition arm ( 4110 ) and configured to reduce piston stroke of the piston assembly ( 4105 ) upon application of an overload to the assembly while enabling the rotating member ( 4130 ), e.g., an input drive and/or a flywheel, to continue rotating. The overload protection mechanism ( 4135 ) is configured to reduce piston stroke of the piston assembly to zero stroke while enabling the rotating member ( 4130 ) to continue rotating at a substantially pre-overload speed. A method of protecting an assembly from an overload includes reducing piston stroke upon application of an overload to the assembly while enabling the rotating member ( 4130 ) to continue rotating at a substantially pre-overload speed.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from U.S. Provisional Application No.60/383,139 filed May 28, 2002, and titled OVERLOAD PROTECTION, which isincorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

This invention relates to an overload protection mechanism used in, forexample, generators, compressors, pumps, integral engine compressors,and integral engine pumps.

Most piston driven engines have pistons that are attached to offsetportions of a crankshaft such that as the pistons are moved in areciprocal direction transverse to the axis of the crankshaft, thecrankshaft will rotate.

U.S. Pat. No. 5,535,709, defines an engine with a double ended pistonthat is attached to a crankshaft with an off set portion. A leverattached between the piston and the crankshaft is restrained in afulcrum regulator to provide the rotating motion to the crankshaft.

U.S. Pat. No. 4,011,842, defines a four cylinder piston engine thatutilizes two double ended pistons connected to a T-shaped connectingmember that causes a crankshaft to rotate. The T-shaped connectingmember is attached at each of the T-cross arm to a double ended piston.A centrally located point on the T-cross arm is rotatably attached to afixed point, and the bottom of the T is rotatably attached to a crankpin which is connected to the crankshaft by a crankthrow which includesa counter weight.

In each of the above examples, double ended pistons are used that drivea crankshaft that has an axis transverse to the axis of the pistons.

SUMMARY OF THE INVENTION

According to one aspect of the invention, an assembly includes at leastone piston assembly, a rotating member, and a transition arm. Thetransition arm couples the piston assembly to the rotating member. Theassembly includes an overload protection mechanism coupled to thetransition arm and configured to reduce piston stroke of the pistonassembly upon application of an overload to the assembly while enablingthe rotating member to continue rotating.

Embodiments of this aspect of the invention may include one or more ofthe following features.

The rotating member is a flywheel and the transition arm and theoverload protection mechanism are coupled within the flywheel.Alternatively, the assembly includes a control rod for adjusting theoperating piston stroke of the piston assembly and the overloadprotection mechanism is coupled to the transition arm by the controlrod.

The overload protection mechanism is configured to reduce piston strokeof the piston assembly, e.g., to zero stroke, while enabling therotating member, e.g., an input drive and/or a flywheel, to continuerotating at a substantially pre-overload speed.

In an illustrated embodiment, the rotating member defines a slot and theoverload protection mechanism includes at least one spring positioned inthe slot and configured to bias the transition arm towards an operatingstroke position. The slot is bounded by a plurality of differentsurfaces sized and shaped to guide the transition arm from an operatingstroke position to a reduced stroke position upon application of theoverload. The spring is, e.g., a coil spring or a leaf spring.

The assembly includes a control rod for adjusting the operating strokeof the piston assembly. The overload protection mechanism is coupled tothe control rod and includes a spring and a control rod extensioncoupled to the spring. The assembly includes a force applicator, e.g., ahydraulic cylinder, coupled to the control rod extension. The spring hasa spring force selected such that application of a load on the controlrod extension by the force applicator to adjust piston stroke istransferred to the control rod by the spring, and application of anoverload to the spring by the control rod causes the spring to compressto allow a decrease in piston stroke.

The overload protection mechanism is configured to increase pistonstroke upon removal of the overload. The assembly includes at leastthree piston assemblies, and the transition arm couples each pistonassembly to the rotating member.

According to another aspect of the invention, an overload protectionmechanism protects an assembly from damage due to an overload. Theassembly includes at least one piston assembly and a transition armcoupled to the piston assembly. The overload protection mechanismincludes a biasing member configured and arranged to bias the transitionarm towards an operating stroke position, and react in response toapplication of an overload such that the position of the transition armis adjusted to reduce piston stroke of the piston assembly.

According to another aspect of the invention, an overload protectionmechanism protects an assembly from damage due to an overload. Theassembly includes at least one piston assembly and a control rod foradjusting operating stroke of the piston assembly. The overloadprotection mechanism includes a control rod extension configured toreceive a load for adjusting the operating stroke of the pistonassembly, and a spring acting between the control rod and the controlrod extension. The spring has a spring force selected such thatapplication of the load on the control rod extension to adjust pistonstroke is transferred to the control rod by the spring, and anapplication of an overload to the spring by the control rod causes thespring to compress to allow a decrease in piston stroke.

According to another aspect of the invention, a method of protecting anassembly from an overload includes reducing piston stroke uponapplication of an overload to the assembly while enabling a rotatingmember, e.g., an input drive and/or a flywheel, to continue rotating ata substantially pre-overload speed.

Embodiments of this aspect of the invention may include reducing pistonstroke to zero.

According to another aspect of the invention, an assembly includes atleast one piston assembly, a rotating member, and a transition armcoupling the piston assembly to the rotating member. The assemblyincludes a means for reducing piston stroke of the piston assembly uponapplication of an overload to the assembly while enabling the rotatingmember to continue rotating.

Advantages of the invention may include the ability to reduce stroke tolimit damage due to an overload while maintaining the rotational inertiaof the flywheel and the input drive. The stroke can be reduced to zerosuch that the pistons are not acting against the overload, while theinput drive and flywheel can continue to rotate to reduce start-up timewhen the overload is removed.

The details of one or more features of the invention are set forth inthe accompanying drawings and the description below. Other features andadvantages of the invention will be apparent from the description anddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 are side view of a simplified illustration of a fourcylinder engine of the present invention;

FIGS. 3, 4, 5 and 6 are a top views of the engine of FIG. 1 showing thepistons and flywheel in four different positions;

FIG. 7 is a top view, partially in cross-section of an eight cylinderengine of the present invention;

FIG. 8 is a side view in cross-section of the engine of FIG. 7;

FIG. 9 is a right end view of FIG. 7;

FIG. 10 is a side view of FIG. 7;

FIG. 11 is a left end view of FIG. 7;

FIG. 12 is a partial top view of the engine of FIG. 7 showing thepistons, drive member and flywheel in a high compression position;

FIG. 13 is a partial top view of the engine in FIG. 7 showing thepistons, drive member and flywheel in a low compression position;

FIG. 14 is a top view of a piston;

FIG. 15 is a side view of a piston showing the drive member in twopositions;

FIG. 16 shows the bearing interface of the drive member and the piston;

FIG. 17 is an air driven engine/pump embodiment;

FIG. 18 illustrates the air valve in a first position;

FIGS. 18 a, 18 b and 18 c are cross-sectional view of threecross-sections of the air valve shown in FIG. 18;

FIG. 19 illustrates the air valve in a second position;

FIGS. 19 a, 19 b and 19 c are cross-sectional view of threecross-sections for the air valve shown in FIG. 19;

FIG. 20 shows an embodiment with slanted cylinders;

FIG. 21 shows an embodiment with single ended pistons;

FIG. 22 is a top view of a two cylinder, double ended piston assembly;

FIG. 23 is a top view of one of the double ended pistons of the assemblyof FIG. 22;

-   -   s FIG. 23 a is a side view of the double ended piston of FIG.        23, taken along lines 23A, 23A;

FIG. 24 is a top view of a transition arm and universal joint of thepiston assembly of FIG. 22;

FIG. 24 a is a side view of the transition arm and universal joint ofFIG. 24, taken along lines 24 a, 24 a;

FIG. 25 is a perspective view of a drive arm connected to the transitionarm of the piston assembly of FIG. 22;

FIG. 25 a is an end view of a rotatable member of the piston assembly ofFIG. 22, taken along lines 25 a, 25 a of FIG. 22, and showing theconnection of the drive arm to the rotatable member;

FIG. 25 b is a side view of the rotatable member, taken along lines 25b, 25 b of FIG. 25 a;

FIG. 26 is a cross-sectional, top view of the piston assembly of FIG.22;

FIG. 27 is an end view of the transition arm, taken along lines 27, 27of FIG. 24;

FIG. 27 a is a cross-sectional view of a drive pin of the pistonassembly of FIG. 22;

FIGS. 28-28 b are top, rear, and side views, respectively, of the pistonassembly of FIG. 22;

FIG. 28 c is a top view of an auxiliary shaft of the piston assembly ofFIG. 22;

FIG. 29 is a cross-sectional side view of a zero-stroke coupling;

FIG. 29 a is an exploded view of the zero-stroke coupling of FIG. 29;

FIG. 30 is a graph showing the FIG. 8 motion of a non-flat pistonassembly;

FIG. 31 shows a reinforced drive pin;

FIG. 32 is a top view of a four cylinder engine for directly applyingcombustion pressures to pump pistons;

FIG. 32 a is an end view of the four cylinder engine, taken along lines32 a, 32 a of FIG. 32;

FIG. 33 is a cross-sectional top view of an alternative embodiment of avariable stroke assembly shown in a maximum stroke position;

FIG. 34 is a cross-sectional top view of the embodiment of FIG. 33 shownin a minimum stroke position;

FIG. 35 is a partial, cross-sectional top view of an alternativeembodiment of a double-ended piston joint;

FIG. 35A is an end view and FIG. 35B is a side view of the double-endedpiston joint, taken along lines 35A, 35A and 35B, 35B, respectively, ofFIG. 35;

FIG. 36 is a partial, cross-sectional top view of the double-endedpiston joint of FIG. 35 shown in a rotated position;

FIG. 37 is a side view of an alternative embodiment of the joint of FIG.35;

FIG. 38 is atop view of an engine/compressor assembly;

FIG. 38A is an end view and FIG. 38B is a side view of theengine/compressor assembly, taken along lines 38A, 38A and 38B, 38B,respectively, of FIG. 38;

FIG. 39 is a perspective view of a piston engine assembly includingcounterbalancing;

FIG. 40 is a perspective view of the piston engine assembly of FIG. 39in a second position;

FIG. 41 is a perspective view of an alternative embodiment of a pistonengine assembly including counterbalancing;

FIG. 42 is a perspective view of the piston engine assembly of FIG. 41in a second position.

FIG. 43 is a perspective view of an additional alternative embodiment ofa piston engine assembly including counterbalancing;

FIG. 44 is a perspective view of the piston engine assembly of FIG. 43in a second position;

FIG. 45 is a perspective view of an additional alternative embodiment ofa piston engine assembly including counterbalancing;

FIG. 46 is a perspective view of the piston engine assembly of FIG. 43in a second position;

FIG. 47 is a side view showing the coupling of a transition arm to aflywheel;

FIG. 48 is a side view of an alternative coupling of the transition armto the flywheel;

FIG. 49 is a side view of an additional alternative coupling of thetransition arm to the flywheel;

FIG. 50 is a cross-sectional side view of a hydraulic pump;

FIG. 51 is an end view of a face valve of the hydraulic pump of FIG. 50;

FIG. 52 is a cross-sectional view of the hydraulic pump of FIG. 30,taken along lines 52-52;

FIG. 53 is an end view of a face plate of the hydraulic pump of FIG. 50;

FIG. 54 is a partially cut-away side view of a variable compressionpiston assembly;

FIG. 55 is a cross-sectional side view of the piston assembly of FIG.54, taken along lines 55-55;

FIG. 56 is a side view of an alternative embodiment of a piston joint;

FIGS. 56A and 56B are top and end views, respectively, of the pistonjoint of FIG. 56;

FIG. 56C is an exploded perspective view of the piston joint of FIG. 56;

FIG. 56D is an exploded view of inner and outer members of the pistonjoint of FIG. 56;

FIGS. 56E and 56F are side and inner face views, respectively, of anouter member of the piston joint of FIG. 56;

FIG. 57 illustrates the piston assembly of FIG. 54 with a balancemember;

FIG. 58 is a partial cross-sectional view of a compressor with a linearstroke/clearance control mechanism;

FIG. 59 is a graph showing the top dead center clearance as stroke isvaried in the compressor of FIG. 58;

FIG. 60 is a partial cross-sectional view of a compressor with anon-linear stroke/clearance control mechanism;

FIG. 61 is a cross-sectional view of an integral motor/compressor;

FIG. 62 is a cross-sectional view of the integral motor/compressor ofFIG. 61 incorporating a linear stroke/clearance control mechanism;

FIG. 63 is an illustration of a metering pump;

FIG. 64 is a simplified, isometric view of the metering pump of FIG. 63with components removed for ease of illustration;

FIG. 65 is an illustration of a linear generator/motor assembly;

FIG. 66 is an illustration of an alternative embodiment of a magnet andcoil of the assembly of FIG. 65;

FIG. 67 is an illustration of a compressor or pump assembly including asingle linear motor;

FIG. 68 is an illustration of a piston assembly that converts betweenphases;

FIG. 69 is an illustration of an output shaft of one piston assemblydriving another piston assembly;

FIG. 70 is an illustration of a drive assembly with an overloadprotection mechanism;

FIG. 71 is an illustration of a portion of the drive assembly of FIG.70;

FIG. 72 is an end view of the overload protection mechanism taken alonglines 72-72 of FIG. 71;

FIG. 73 is a cross-sectional view of a flywheel of the drive assembly ofFIG. 70;

FIG. 74 is a perspective view of a block of the drive assembly of FIG.70;

FIG. 75 is a perspective view of a pad of the drive assembly of FIG. 70used in an optional shut-off or light indicator mechanism;

FIG. 76A is an illustration of a portion of the drive assembly of FIG.70;

FIG. 76B is an end view of the overload protection mechanism of FIG. 76Ataken along lines 76B-76B of FIG. 76A;

FIG. 76C is an illustration of the drive assembly of FIG. 76A with theoverload protection mechanism responding to a downstream blockage;

FIG. 76D is an end view of the overload protection mechanism of FIG. 76Ctaken along lines 76D-76D of FIG. 76C;

FIG. 77 is an illustration of a portion of a drive assembly with analternative implementation of an overload protection mechanism;

FIG. 78 is an end view of the overload protection mechanism of FIG. 77taken along lines 78-78 of FIG. 77;

FIG. 79 is an exploded view of a spring retainer ring, a leaf spring,and a flywheel of the drive assembly of FIG. 77;

FIG. 80 is a cross-sectional view of the flywheel of the drive assemblyof FIG. 77;

FIG. 81 is an illustration of a variable stroke pump assembly with analternative embodiment of an overload protection mechanism; and

FIG. 82 is an illustration of the overload protection mechanism of FIG.81.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a pictorial representation of a four piston engine 10 of thepresent invention. Engine 10 has two cylinders 11 (FIG. 3) and 12. Eachcylinder 11 and 12 house a double ended piston. Each double ended pistonis connected to transition arm 13 which is connected to flywheel 15 byshaft 14. Transition arm 13 is connected to support 19 by a universaljoint mechanism, including shaft 18, which allows transition arm 13 tomove up an down and shaft 17 which allows transition arm 13 to move sideto side. FIG. 1 shows flywheel 15 in a position shaft 14 at the top ofwheel 15.

FIG. 2 shows engine 10 with flywheel 15 rotated so that shaft 14 is atthe bottom of flywheel 15. Transition arm 13 has pivoted downward onshaft 18.

FIGS. 3-6 show a top view of the pictorial representation, showing thetransition arm 13 in four positions and shaft moving flywheel 15 in 90°increments.

FIG. 3 shows flywheel 15 with shaft 14 in the position as illustrated inFIG. 3 a. When piston 1 fires and moves toward the middle of cylinder11, transition arm 13 will pivot on universal joint 16 rotating flywheel15 to the position shown in FIG. 2. Shaft 14 will be in the positionshown in FIG. 4 a. When piston 4 is fired, transition arm 13 will moveto the position shown in FIG. 5. Flywheel 15 and shaft 14 will be in theposition shown in FIG. 5 a Next piston 2 will fire and transition arm 13will be moved to the position shown in FIG. 6. Flywheel 15 and shaft 14will be in the position shown in FIG. 6 a. When piston 3 is fired,transition arm 13 and flywheel 15 will return to the original positionthat shown in FIGS. 3 and 3 a. When the pistons fire, transition armwill be moved back and forth with the movement of the pistons. Sincetransition arm 13 is connected to universal joint 16 and to flywheel 15through shaft 14, flywheel 15 rotates translating the linear motion ofthe pistons to a rotational motion.

FIG. 7 shows (in partial cross-section) a top view of an embodiment of afour double piston, eight cylinder engine 30 according to the presentinvention. There are actually only four cylinders, but with a doublepiston in each cylinder, the engine is equivalent to a eight cylinderengine. Two cylinders 31 and 46 are shown. Cylinder 31 has double endedpiston 32, 33 with piston rings 32 a and 33 a, respectively. Pistons 32,33 are connected to a transition arm 60 (FIG. 8) by piston arm 54 aextending into opening 55 a in piston 32, 33 and sleeve bearing 55.Similarly piston 47, 49, in cylinder 46 is connected by piston arm 54 bto transition arm 60.

Each end of cylinder 31 has inlet and outlet valves controlled by arocker arms and a spark plug. Piston end 32 has rocker arms 35 a and 35b and spark plug 44, and piston end 33 has rocker arms 34 a and 34 b,and spark plug 41. Each piston has associated with it a set of valves,rocker arms and a spark plug. Timing for firing the spark plugs andopening and closing the inlet and exhaust values is controlled by atiming belt 51 which is connected to pulley 50 a. Pulley 50 a isattached to a gear 64 by shaft 63 (FIG. 8) turned by output shaft 53powered by flywheel 69. Belt 50 a also turns pulley 50 b and gear 39connected to distributor 38. Gear 39 also turns gear 40. Gears 39 and 40are attached to cam shaft 75 (FIG. 8) which in turn activate push rodsthat are attached to the rocker arms 34, 35 and other rocker arms notillustrated.

Exhaust manifolds 48 and 56 as shown attached to cylinders 46 and 31respectively. Each exhaust manifold is attached to four exhaust ports.

FIG. 8 is a side view of engine 30, with one side removed, and takenthrough section 8-8 of FIG. 7. Transitions arm 60 is mounted on support70 by pin 72 which allows transition arm to move up and down (as viewedin FIG. 8) and pin 71 which allows transition arm 60 to move from sideto side. Since transition arm 60 can move up and down while moving sideto side, then shaft 61 can drive flywheel 69 in a circular path. Thefour connecting piston arms (piston arms 54 b and 54 d shown in FIG. 8)are driven by the four double end pistons in an oscillator motion aroundpin 71. The end of shaft 61 in flywheel 69 causes transition arm to moveup and down as the connection arms move back and forth. Flywheel 69 hasgear teeth 69 a around one side which may be used for turning theflywheel with a starter motor 100 (FIG. 11) to start the engine.

The rotation of flywheel 69 and drive shaft 68 connected thereto, turnsgear 65 which in turn turns gears 64 and 66. Gear 64 is attached toshaft 63 which turns pulley 50 a. Pulley 50 a is attached to belt 51.Belt 51 turns pulley 50 b and gears 39 and 40 (FIG. 7). Cam shaft 75 hascams 88-91 on one end and cams 84-87 on the other end. Cams 88 and 90actuate push rods 76 and 77, respectively. Cams 89 and 91 actuate pushrods 93 and 94, respectively. Cams 84 and 86 actuate push rods 95 and96, respectively, and cams 85 and 87 actuate push rods 78 and 79,respectively. Push rods 77, 76, 93, 94, 95, 96 and 78, 79 are foropening and closing the intake and exhaust valves of the cylinders abovethe pistons. The left side of the engine, which has been cutaway,contains an identical, but opposite valve drive mechanism.

Gear 66 turned by gear 65 on drive shaft 68 turns pump 67, which may be,for example, a water pump used in the engine cooling system (notillustrated), or an oil pump.

FIG. 9 is a rear view of engine 30 showing the relative positions of thecylinders and double ended pistons. Piston 32, 33 is shown in dashedlines with valves 35 c and 35 d located under lifter arms 35 a and 35 b,respectively. Belt 51 and pulley 50 b are shown under distributor 38.Transition arm 60 and two, 54 c and 54 d, of the four piston arms 54 a,54 b, 54 c and 54 d are shown in the pistons 32-33, 32 a-33 a, 47-49 and47 a-49 a.

FIG. 10 is a side view of engine 30 showing the exhaust manifold 56,intake manifold 56 a and carburetor 56 c. Pulleys 50 a and 50 b withtiming belt 51 are also shown.

FIG. 11 is a front end view of engine 30 showing the relative positionsof the cylinders and double ended pistons 32-33, 32 a-33 a, 47-49 and 47a-49 a with the four piston arms 54 a, 54 b, 54 c and 54 d positioned inthe pistons. Pump 67 is shown below shaft 53, and pulley 50 a and timingbelt 51 are shown at the top of engine 30. Starter 100 is shown withgear 101 engaging the gear teeth 69 a on flywheel 69.

A feature of the invention is that the compression ratio for the enginecan be changed while the engine is running. The end of arm 61 mounted inflywheel 69 travels in a circle at the point where arm 61 entersflywheel 69. Referring to FIG. 13, the end of arm 61 is in a sleevebearing ball bushing assembly 81. The stroke of the pistons iscontrolled by arm 61. Arm 61 forms an angle, for example about 15°, withshaft 53. By moving flywheel 69 on shaft 53 to the right or left, asviewed in FIG. 13, the angle of arm 61 can be changed, changing thestroke of the pistons, changing the compression ratio. The position offlywheel 69 is changed by turning nut 104 on threads 105. Nut 104 iskeyed to shaft 53 by thrust bearing 106 a held in place by ring 106 b.In the position shown in FIG. 12, flywheel 69 has been moved to theright, extending the stroke of the pistons.

FIG. 12 shows flywheel moved to the right increasing the stroke of thepistons, providing a higher compression ratio. Nut 105 has been screwedto the right, moving shaft 53 and flywheel 69 to the right. Arm 61extends further into bushing assembly 80 and out the back of flywheel69.

FIG. 13 shows flywheel moved to the left reducing the stroke of thepistons, providing a lower compression ratio. Nut 105 has been screwedto the left, moving shaft 53 and flywheel 69 to the left. Arm 61 extendsless into bushing assembly 80.

The piston arms on the transition arm are inserted into sleeve bearingsin a bushing in piston. FIG. 14 shows a double piston 110 having pistonrings 111 on one end of the double piston and piston rings 112 on theother end of the double piston. A slot 113 is in the side of the piston.The location the sleeve bearing is shown at 114.

FIG. 15 shows a piston arm 116 extending into piston 110 through slot116 into sleeve bearing 117 in bushing 115. Piston arm 116 is shown in asecond position at 116 a. The two pistons arms 116 and 116 a show themovement limits of piston arm 116 during operation of the engine.

FIG. 16 shows piston arm 116 in sleeve bearing 117. Sleeve bearing 117is in pivot pin 115. Piston arm 116 can freely rotate in sleeve bearing117 and the assembly of piston arm 116. Sleeve bearing 117 and pivot pin115 and sleeve bearings 118 a and 118 b rotate in piston 110, and pistonarm 116 can be moved axially with the axis of sleeve bearing 117 toallow for the linear motion of double ended piston 110, and the motionof a transition arm to which piston arm 116 is attached.

FIG. 17 shows how the four cylinder engine 10 in FIG. 1 may beconfigured as an air motor using a four way rotary valve 123 on theoutput shaft 122. Each of cylinders 1, 2, 3 and 4 are connected by hoses131. 132, 133, and 144, respectively, to rotary valve 123. Air inletport 124 is used to supply air to run engine 120. Air is sequentiallysupplied to each of the pistons 1 a, 2 a, 3 a and 4 a, to move thepistons back and forth in the cylinders. Air is exhausted from thecylinders out exhaust port 136. Transition arm 126, attached to thepistons by connecting pins 127 and 128 are moved as described withreferences to FIGS. 1-6 to turn flywheel 129 and output shaft 22.

FIG. 18 is a cross-sectional view of rotary valve 123 in the positionwhen pressurized air or gas is being applied to cylinder 1 through inletport 124, annular channel 125, channel 126, channel 130, and air hose131. Rotary valve 123 is made up of a plurality of channels in housing123 and output shaft 122. The pressurized air entering cylinder 1 causespiston 1 a, 3 a to move to the right (as viewed in FIG. 18). Exhaust airis forced out of cylinder 3 through line 133 into chamber 134, throughpassageway 135 and out exhaust outlet 136.

FIGS. 18 a, 18 b and 18 c are cross-sectional view of valve 23 showingthe air passages of the valves at three positions along valve 23 whenpositioned as shown in FIG. 18.

FIG. 19 shows rotary valve 123 rotated 180° when pressurized air isapplied to cylinder 3, reversing the direction of piston 1 a, 3 a.Pressurized air is applied to inlet port 124, through annular chamber125, passage way 126, chamber 134 and air line 133 to cylinder 3. Thisin turn causes air in cylinder 1 to be exhausted through line 131,chamber 130, line 135, annular chamber 137 and out exhaust port 136.Shaft 122 will have rotated 360° turning counter clockwise when piston 1a, 3 a complete it stroke to the left.

Only piston 1 a,3 a have been illustrated to show the operation of theair engine and valve 123 relative to the piston motion. The operation ofpiston 2 a,4 a is identical in function except that its 360° cyclestarts at 90° shaft rotation and reverses at 270° and completes itscycle back at 90°. A power stroke occurs at every 90° of rotation.

FIGS. 19 a, 19 b and 19 c are cross-sectional views of valve 123 showingthe air passages of the valves at three positions along valve 123 whenpositioned as shown in FIG. 19.

The principle of operation which operates the air engine of FIG. 17 canbe reversed, and engine 120 of FIG. 17 can be used as an air or gascompressor or pump. By rotating engine 10 clockwise by applying rotarypower to shaft 122, exhaust port 136 will draw in air into the cylindersand port 124 will supply air which may be used to drive, for example airtool, or be stored in an air tank.

In the above embodiments, the cylinders have been illustrated as beingparallel to each other. However, the cylinders need not be parallel.FIG. 20 shows an embodiment similar to the embodiment of FIG. 1-6, withcylinders 150 and 151 not parallel to each other. Universal joint 160permits the piston arms 152 and 153 to be at an angle other than 90° tothe drive arm 154. Even with the cylinders not parallel to each otherthe engines are functionally the same.

Still another modification may be made to the engine 10 of FIGS. 1-6.This embodiment, pictorially shown in FIG. 21, may have single endedpistons. Piston 1 a and 2 a are connected to universal joint 170 bydrive arms 171 and 172, and to flywheel 173 by drive arm 174. The basicdifference is the number of strokes of pistons 1 a and 2 a to rotateflywheel 173 360°.

Referring to FIG. 22, a two cylinder piston assembly 300 includescylinders 302, 304, each housing a variable stroke, double ended piston306, 308, respectively. Piston assembly 300 provides the same number ofpower strokes per revolution as a conventional four cylinder engine.Each double ended piston 306, 308 is connected to a transition arm 310by a drive pin 312, 314, respectively. Transition arm 310 is mounted toa support 316 by, e.g., a universal joint 318 (U-joint), constantvelocity joint, or spherical bearing. A drive arm 320 extending fromtransition arm 310 is connected to a rotatable member, e.g., flywheel322.

Transition arm 310 transmits linear motion of pistons 306, 308 to rotarymotion of flywheel 322. The axis, A, of flywheel 322 is parallel to theaxes, B and C, of pistons 306, 308 (though axis, A, could be off-axis asshown in FIG. 20) to form an axial or barrel type engine, pump, orcompressor. U-joint 318 is centered on axis, A. As shown in FIG. 28 a,pistons 306, 308 are 180? apart with axes A, B and C lying along acommon plane, D, to form a flat piston assembly.

Referring to FIGS. 22 and 23, cylinders 302, 304 each include left andright cylinder halves 301 a, 301 b mounted to the assembly casestructure 303. Double ended pistons 306, 308 each include two pistons330 and 332, 330 a and 332 a, respectively, joined by a central joint334, 334 a, respectively. The pistons are shown having equal length,though other lengths are contemplated. For example, joint 334 can beoff-center such that piston 330 is longer than piston 332. As thepistons are fired in sequence 330 a, 332, 330, 332 a, from the positionshown in FIG. 22, flywheel 322 is rotated in a clockwise direction, asviewed in the direction of arrow 333. Piston assembly 300 is a fourstroke cycle engine, i.e., each piston fires once in two revolutions offlywheel 322.

As the pistons move back and forth, drive pins 312, 314 must be free torotate about their common axis, E, (arrow 305), slide along axis, E,(arrow 307) as the radial distance to the center line, B, of the pistonchanges with the angle of swing, α, of transition arm 310 (approximately±15° swing), and pivot about centers, F, (arrow 309). Joint 334 isconstructed to provide this freedom of motion.

Joint 334 defines a slot 340 (FIG. 23 a) for receiving drive pin 312,and a hole 336 perpendicular to slot 340 housing a sleeve bearing 338. Acylinder 341 is positioned within sleeve bearing 338 for rotation withinthe sleeve bearing. Sleeve bearing 338 defines a side slot 342 shapedlike slot 340 and aligned with slot 340. Cylinder 341 defines a throughhole 344. Drive pin 312 is received within slot 342 and hole 344. Anadditional sleeve bearing 346 is located in through hole 344 of cylinder341. The combination of slots 340 and 342 and sleeve bearing 338 permitdrive pin 312 to move along arrow 309. Sleeve bearing 346 permits drivepin 312 to rotate about its axis, E, and slide along its axis, E.

If the two cylinders of the piston assembly are configured other than180° apart, or more than two cylinders are employed, movement ofcylinder 341 in sleeve bearing 338 along the direction of arrow 350allows for the additional freedom of motion required to prevent bindingof the pistons as they undergo a FIG. 8 motion, discussed below. Slot340 must also be sized to provide enough clearance to allow the FIG. 8motion of the pin.

Referring to FIGS. 35-35B, an alternative embodiment of a central joint934 for joining pistons 330 and 332 is configured to produce zero sideload on pistons 330 and 332. Joint 934 permits the four degrees offreedom necessary to prevent binding of drive pin 312 as the pistonsmove back and forth, i.e., rotation about axis, E, (arrow 905), pivotingabout center, F, (arrow 909), and sliding movement along orthogonalaxes, M (up and down in the plane of the paper in FIG. 35) and N (in andout of the plane of the paper in FIG. 35), while the load transmittedbetween joint 934 and pistons 330, 332 only produces a force vectorwhich is parallel to piston axis, B (which is orthogonal to axes M andN).

Sliding movement along axis, M, accommodates the change in the radialdistance of transition arm 310 to the center line, B, of the piston withthe angle of swing, α, of transition arm 310. Sliding movement alongaxis, N, allows for the additional freedom of motion required to preventbinding of the pistons as they undergo the figure eight motion,discussed below. Joint 934 defines two opposed flat faces 937, 937 awhich slide in the directions of axes M and N relative to pistons 330,332. Faces 937, 937 a define parallel planes which remain perpendicularto piston axis, B, during the back and forth movement of the pistons.

Joint 934 includes an outer slider member 935 which defines faces 937,937 a for receiving the driving force from pistons 330, 332. Slidermember 935 defines a slot 940 in a third face 945 of the slider forreceiving drive pin 312, and a slot 940 a in a fourth face 945 a. Slidermember 935 has an inner wall 936 defining a hole 939 perpendicular toslot 940 and housing a slider sleeve bearing 938. A cross shaft 941 ispositioned within sleeve bearing 938 for rotation within the sleevebearing in the direction of arrow 909. Sleeve bearing 938 defines a sideslot 942 shaped like slot 940 and aligned with slot 940. Cross shaft 941defines a through hole 944. Drive pin 312 is received within slot 942and hole 944. A sleeve bearing 946 is located in through hole 944 ofcross shaft 941.

The combination of slots 940 and 942 and sleeve bearing 938 permit drivepin 312 to move in the direction of arrow 909. Positioned within slot940 a is a cap screw 947 and washer 949 which attach to drive pin 312retaining drive pin 312 against a step 951 defined by cross shaft 941while permitting drive pin 312 to rotate about its axis, E, andpreventing drive pin 312 from sliding along axis, E. As discussed above,the two addition freedoms of motion are provided by sliding of sliderfaces 937, 937 a relative to pistons 330, 332 along axis, M and N. Aplate 960 is placed between each of face 937 and piston 330 and face 937a and piston 332. Each plate 960 is formed of a low friction bearingmaterial with a bearing surface 962 in contact with faces 937, 937 a,respectively. Faces 937, 937 a are polished.

As shown in FIG. 36, the load, P_(L), applied to joint 934 by piston 330in the direction of piston axis, B, is resolved into two perpendicularloads acting on pin 312: axial load, A_(L), along the axis, E, of drivepin 312, and normal load, N_(L), perpendicular to drive pin axis, E. Theaxial load is applied to thrust bearings 950, 952, and the normal loadis applied to sleeve bearing 946. The net direction of the forcestransmitted between pistons 330, 332 and joint 934 remains along pistonaxis, B, preventing side loads being applied to pistons 330, 332. Thisis advantageous because side loads on pistons 330, 332 can cause thepistons to contact the cylinder wall creating frictional lossesproportional to the side load values.

Pistons 330, 332 are mounted to joint 934 by a center piece connector970. Center piece 970 includes threaded ends 972, 974 for receivingthreaded ends 330 a and 332 a of the pistons, respectively. Center piece970 defines a cavity 975 for receiving joint 934. A gap 976 is providedbetween joint 934 and center piece 970 to permit motion along axis, N.

For an engine capable of producing, e.g., about 100 horsepower, joint934 has a width, W, of, e.g., about 3 5/16 inches, a length, L₁, of,e.g., 3 5/16 inches, and a height, H, of, e.g., about 3½ inches. Thejoint and piston ends together have an overall length, L₂, of, e.g.,about 9 5/16inches, and a diameter, D₁, of, e.g., about 4 inches. Plates960 have a diameter, D₂, of, e.g., about 3¼ inch, and a thickness, T,of, e.g., about 1/8 inch. Plates 960 are press fit into the pistons.Plates 960 are preferably bronze, and slider 935 is preferably steel oraluminum with a steel surface defining faces 937, 937 a.

Joint 934 need not be used to join two pistons. One of pistons 330, 332can be replaced by a rod guided in a bushing.

Where figure eight motion is not required or is allowed by motion ofdrive pin 312 within cross shaft 941, joint 934 need not slide in thedirection of axis, N. Referring to FIG. 37, slider member 935 a andplates 960 a have curved surfaces permitting slider member 935 a toslide in the direction of axis, M, (in and out of the paper in FIG. 37)while preventing slider member 935 a to move along axis, N.

Referring to FIGS. 56-56F, a piston joint 2300 includes a housing 2302,an outer member 2304 having first and second parts 2304 a, 2304 b, andan inner cylindrical member 2306. Housing 2302 includes extensions 2308and a rectangular shaped enclosure 2310. In FIG. 56, one extension 2308includes a mount 2308 a to which a piston or plunger (not shown) iscoupled, with the opposite extension 2308 acting as guide rods. In FIG.56A, both extensions 2308 are shown with mounts 2308 a to which adouble-ended piston or plunger is coupled. Enclosure 2310 defines arectangular shaped opening 2312 (FIG. 56C) in which outer member 2304and inner member 2306 are positioned. Opening 2312 is defined by fourflat inner walls 2312 a, 2312 b, 2312 c, 2312 d of enclosure 2310.

Referring particularly to FIGS. 56C and 56D, parts 2304 a, 2304 b eachhave a flat outer, end wall 2314, defining a plane perpendicular to anaxis, X, defined by mounts 2308, two parallel flat sides 2316, and twocurved side walls 2318. Parts 2304 a, 2304 b also have an inner end wall2320 with a concave cut-out 2322. When assembled, concave cut-outs 2322define an opening 2322 a (FIG. 56A) between parts 2304 a, 2304 b forreceiving inner member 2306. Inner end wall 2320 also defines two,sloped concave cut-outs 2324 perpendicular to cut-outs 2322 andpositioned between sloped edges 2326, for purposes described below.Parts 2304 a, 2304 b are sized relative to opening 2312 to be free toslide along an axis, Y, perpendicular to axis, X, (arrow A), but arerestricted by walls 2312 a, 2312 b from sliding along an axis, Z,perpendicular to axes, X and Y (arrow B).

Inner member 2306 defines a through hole 2330 for receiving a transitionarm drive arm 2332. Inner member 2306 is shorter in the Z direction thanopening 2312 in housing 2302 such that inner member 2306 can slidewithin opening 2312 along axis, Z, (arrow B). Located between drive arm2332 and inner member 2306 is a sleeve bearing 2334 which facilitatesrotation of drive arm 2332 relative to inner member 2306 about axis, Y,arrow (D) (FIG. 56D). Drive arm 2332 is coupled to inner member 2306 bya threaded stud 2338, washer 2340, nut 2342, and thrust washers 2344 and2346. Stud 2338 is received within a threaded hole 2339 in arm 2332.Inner member 2306 is countersunk at 2306 a to receive washer 2346.Thrust washer 2346 includes a tab 2348 received in a notch (not shown)in inner member 2306 to prevent rotation of thrust washer 2346 relativeto inner member 2306. Thrust washer 2344 is formed, e.g., of steel, witha polished surface facing thrust washer 2346. Thrust washer 2346 has,e.g., a Teflon surface facing thrust washer 2344 to provide low frictionbetween washers 2344 and 2346, and a copper backing. An additionalthrust washer 2350, formed, e.g., of bronze, is positioned between innermember 2306 and the transition arm.

Piston joint 2300 includes an oil path 2336 (FIG. 56A) for flow oflubrication. Arm 2332, inner member 2306, outer member parts 2304 a and2304 b, and bearing 2334 include through holes 2352 that define oil path2336. Alternatively, bearing 2334 can be formed from two rings with agap between the rings for flow of oil.

In operation, outer member 2304 and inner member 2306 slide togetherrelative to housing 2302 along axis, Y, (arrow A), inner member 2306slides relative to outer member 2304 along axis, Z, (arrow B), innermember 2306 rotates relative to outer member 2304 about axis, Z, (arrowC), and drive arm 2332 rotates relative to inner member 2306 about axis,Y, (arrow D). Load is transferred between outer member 2304 and housing2302 along vectors parallel to axis, X, by flat sides 2314 of outermember 2304 and flat walls 2312 c and 2312 d of housing 2302, thuslimiting the transfer of any side loads to the pistons.

Depending on the layout and number of cylinders, motion of drive arm2332 can also cause inner member 2306 to rotate about axis, X. Forexample, in a three cylinder pump, with the top cylinder in line withthe U-joint fixed axis, and the second and third cylinders spaced 120degrees, the drive arms for the second and third cylinders undergo atwisting motion which is part of the FIG. 8 motion describe above. Thismotion causes rotation of inner member 2306 of the respective jointsabout axis, X. This twisting motion is taking place at twice the rpmfrequency. Unless further steps are taken, housing 2302 and the pistonswould also twist about axis, X, at twice the rpm frequency. Inner member2306 of the joint for the top piston does not undergo twist about axis,X, because its drive pin is confined to motion in a straight line by theU-joint.

In the piston joint of FIG. 35, outer member 935 is free to rotate aboutaxis, B (corresponding to axis, X of FIG. 56), thus the twisting motionof the drive arm is not transferred to the pistons. In the piston jointof FIG. 56, since outer member 2304 is restrained from moving in thedirection of axis, Z, curved side walls 2318 of parts 2304 a, 2304 b areprovided for accommodating the motion about axis, X. Referringparticularly to FIGS. 56E and 56F, walls 2318 are radiused over anangle, α, of about ±2°, that blends into a tangent plane at the same 2°angle on both sides of a center line, L. This provides another degree offreedom enabling parts 2304 a, 2304 b to rotate within opening 2312about axis, X, in response to motion of inner member 2306 about axis, Xwithout transferring this motion to housing 2302. Since inner member2306 of the joint for the top piston does not undergo this motion, sidewalls 2318 of outer member 2304 of this joint preferably have flat sidesthat allow no angular movement, which controls the angle of the pistonsin the top cylinder.

To maintain control of the angular position of the remaining pistons, itis preferable that curved side walls 2318 have radiused sections whichextend the minimum amount necessary to limit transfer of the motionabout axis, X, to housing 2302. Outer member 2304 acts to nudge thepiston to a set angle on the first revolution of the engine or pump. Ifthe piston deviates from that angle, the piston is forced back by theaction of outer member 2304 at the end of travel of the piston. Thecontact between curved walls 2318 and side walls 2312 a, 2312 b ofhousing 2302 is a line contact, but this contact has no work to do innormal use, and the contact line moves on both parts, distributing anywear taking place.

Referring to FIGS. 24 and 24 a, U-joint 318 defines a central pivot 352(drive pin axis, E, passes through center 352), and includes a verticalpin 354 and a horizontal pin 356. Transition arm 310 is capable ofpivoting about pin 354 along arrow 358, and about pin 356 along arrow360.

Referring to FIGS. 25, 25 a and 25 b, as an alternative to a sphericalbearing, to couple transition arm 310 to flywheel 322, drive arm 320 isreceived within a cylindrical pivot pin 370 mounted to the flywheeloffset radially from the center 372 of the flywheel by an amount, e.g.,2.125 inches, required to produce the desired swing angle, α (FIG. 22),in the transition arm.

Pivot pin 370 has a through hole 374 for receiving drive arm 320. Thereis a sleeve bearing 376 in hole 374 to provide a bearing surface fordrive arm 320. Pivot pin 370 has cylindrical extensions 378, 380positioned within sleeve bearings 382, 384, respectively. As theflywheel is moved axially along drive arm 320 to vary the swing angle,α, and thus the compression ratio of the assembly, as described furtherbelow, pivot pin 370 rotates within sleeve bearings 382, 384 to remainaligned with drive arm 320. Torsional forces are transmitted throughthrust bearings 388, 390, with one or the other of the thrust bearingscarrying the load depending on the direction of the rotation of theflywheel along arrow 386.

Referring to FIG. 26, to vary the compression and displacement of pistonassembly 300, the axial position of flywheel 322 along axis, A, isvaried by rotating a shaft 400. A sprocket 410 is mounted to shaft 400to rotate with shaft 400. A second sprocket 412 is connected to sprocket410 by a roller chain 413. Sprocket 412 is mounted to a threadedrotating barrel 414. Threads 416 of barrel 414 contact threads 418 of astationary outer barrel 420.

Rotation of shaft 400, arrow 401, and thus sprockets 410 and 412, causesrotation of barrel 414. Because outer barrel 420 is fixed, the rotationof barrel 414 causes barrel 414 to move linearly along axis, A, arrow403. Barrel 414 is positioned between a collar 422 and a gear 424, bothfixed to a main drive shaft 408. Drive shaft 408 is in turn fixed toflywheel 322. Thus, movement of barrel 414 along axis, A, is translatedto linear movement of flywheel 322 along axis, A. This results inflywheel 322 sliding along axis, H, of drive arm 320 of transition arm310, changing angle, β, and thus the stroke of the pistons. Thrustbearings 430 are located at both ends of barrel 414, and a sleevebearing 432 is located between barrel 414 and shaft 408.

To maintain the alignment of sprockets 410 and 412, shaft 400 isthreaded at region 402 and is received within a threaded hole 404 of across bar 406 of assembly case structure 303. The ratio of the number ofteeth of sprocket 412 to sprocket 410 is, e.g., 4:1. Therefore, shaft400 must turn four revolutions for a single revolution of barrel 414. Tomaintain alignment, threaded region 402 must have four times the threadsper inch of barrel threads 416, e.g., threaded region 402 has thirty-twothreads per inch, and barrel threads 416 have eight threads per inch.

As the flywheel moves to the right, as viewed in FIG. 26, the stroke ofthe pistons, and thus the compression ratio, is increased. Moving theflywheel to the left decreases the stroke and the compression ratio. Afurther benefit of the change in stroke is a change in the displacementof each piston and therefore the displacement of the engine. Thehorsepower of an internal combustion engine closely relates to thedisplacement of the engine. For example, in the two cylinder, flatengine, the displacement increases by about 20% when the compressionratio is raised from 6:1 to 12:1. This produces approximately 20% morehorsepower due alone to the increase in displacement. The increase incompression ratio also increases the horsepower at the rate of about 5%per point or approximately 25% in horsepower. If the horsepower weremaintained constant and the compression ratio increased from 6:1 to12:1, there would be a reduction in fuel consumption of approximately25%.

The flywheel has sufficient strength to withstand the large centrifugalforces seen when assembly 300 is functioning as an engine. The flywheelposition, and thus the compression ratio of the piston assembly, can bevaried while the piston assembly is running.

Piston assembly 300 includes a pressure lubrication system. The pressureis provided by an engine driven positive displacement pump (not shown)having a pressure relief valve to prevent overpressures. Bearings 430and 432 of drive shaft 408 and the interface of drive arm 320 withflywheel 322 are lubricated via ports 433 (FIG. 26).

Referring to FIG. 27, to lubricate U-joint 318, piston pin joints 306,308, and the cylinder walls, oil under pressure from the oil pump isported through the fixed U-joint bracket to the top and bottom ends ofthe vertical pivot pin 354. Oil ports 450, 452 lead from the verticalpin to openings 454, 456, respectively, in the transition arm. As shownin FIG. 27A, pins 312, 314 each define a through bore 458. Each throughbore 458 is in fluid communication with a respective one of openings454, 456. As shown in FIG. 23, holes 460, 462 in each pin connectthrough slots 461 and ports 463 through sleeve bearing 338 to a chamber465 in each piston. Several oil lines 464 feed out from these chambersand are connected to the skirt 466 of each piston to provide lubricationto the cylinders walls and the piston rings 467. Also leading fromchamber 465 is an orifice to squirt oil directly onto the inside of thetop of each piston for cooling.

Referring to FIGS. 28-28 c, in which assembly 300 is shown configuredfor use as an aircraft engine 300 a, the engine ignition includes twomagnetos 600 to fire the piston spark plugs (not shown). Magnetos 600and a starter 602 are driven by drive gears 604 and 606 (FIG. 28 c),respectively, located on a lower shaft 608 mounted parallel and belowthe main drive shaft 408. Shaft 608 extends the full length of theengine and is driven by gear 424 (FIG. 26) of drive shaft 408 and isgeared with a one to one ratio to drive shaft 408. The gearing for themagnetos reduces their speed to half the speed of shaft 608. Starter 602is geared to provide sufficient torque to start the engine.

Camshafts 610 operate piston push rods 612 through lifters 613.Camshafts 610 are geared down 2 to 1 through bevel gears 614, 616 alsodriven from shaft 608. Center 617 of gears 614, 616 is preferablyaligned with U-joint center 352 such that the camshafts are centered inthe piston cylinders, though other configurations are contemplated. Asingle carburetor 620 is located under the center of the engine withfour induction pipes 622 routed to each of the four cylinder intakevalves (not shown). The cylinder exhaust valves (not shown) exhaust intotwo manifolds 624.

Engine 300 a has a length, L, e.g., of about forty inches, a width, W,e.g., of about twenty-one inches, and a height, H, e.g., of about twentyinches, (excluding support 303).

Referring to FIGS. 29 and 29 a, a variable compression compressor orpump having zero stroke capability is illustrated. Here, flywheel 322 isreplaced by a rotating assembly 500. Assembly 500 includes a hollowshaft 502 and a pivot arm 504 pivotally connected by a pin 506 to a hub508 of shaft 502. Hub 508 defines a hole 510 and pivot arm 504 defines ahole 512 for receiving pin 506. A control rod 514 is located withinshaft 502. Control rod 514 includes a link 516 pivotally connected tothe remainder of rod 514 by a pin 518. Rod 514 defines a hole 511 andlink 516 defines a hole 513 for receiving pin 518. Control rod 514 issupported for movement along its axis, Z, by two sleeve bearings 520.Link 516 and pivot arm 514 are connected by a pin 522. Link 516 definesa hole 523 and pivot arm 514 defines a hole 524 for receiving pin 522.

Cylindrical pivot pin 370 of FIG. 25 which receives drive arm 320 ispositioned within pivot arm 504. Pivot arm 504 defines holes 526 forreceiving cylindrical extensions 378, 380. Shaft 502 is supported forrotation by bearings 530, e.g., ball, sleeve, or roller bearings. Adrive, e.g., pulley 532 or gears, mounted to shaft 502 drives thecompressor or pump.

In operation, to set the desired stroke of the pistons, control rod 514is moved along its axis, M, in the direction of arrow 515, causing pivotarm 504 to pivot about pin 506, along arrow 517, such that pivot pin 370axis, N, is moved out of alignment with axis, M, (as shown in dashedlines) as pivot arm 504 slides along the axis, H, (FIG. 26) of thetransition arm drive arm 320. When zero stroke of the pistons isdesired, axes M and N are aligned such that rotation of shaft 514 doesnot cause movement of the pistons. This configuration works for bothdouble ended and single sided pistons.

The ability to vary the piston stroke permits shaft 514 to be run at asingle speed by drive 532 while the output of the pump or compressor canbe continually varied as needed. When no output is needed, pivot arm 504simply spins around drive arm 320 of transition arm 310 with zero swingof the drive arm. When output is needed, shaft 514 is already running atfull speed so that when pivot arm 504 is pulled off-axis by control rod514, an immediate stroke is produced with no lag coming up to speed.There are therefore much lower stress loads on the drive system as thereare no start/stop actions. The ability to quickly reduce the stroke tozero provides protection from damage especially in liquid pumping when adownstream blockage occurs.

An alternative method of varying the compression and displacement of thepistons is shown in FIG. 33. The mechanism provides for varying of theposition of a counterweight attached to the flywheel to maintain systembalance as the stroke of the pistons is varied.

A flywheel 722 is pivotally mounted to an extension 706 of a main driveshaft 708 by a pin 712. By pivoting flywheel 722 in the direction ofarrow, Z, flywheel 722 slides along axis, H, of a drive arm 720 oftransition arm 710, changing angle, α (FIG. 26), and thus the stroke ofthe pistons. Pivoting flywheel 722 also causes a counterweight 714 tomove closer to or further from axis, A, thus maintaining near rotationalbalance.

To pivot flywheel 722, an axially and rotationally movable pressureplate 820 is provided. Pressure plate 820 is in contact with a roller822 rotationally mounted to counterweight 714 through a pin 824 andbearing 826. From the position shown in FIG. 33, a servo motor or handknob 830 turns a screw 832 which advances to move pressure plate 820 inthe direction of arrow, Y. This motion of pressure plate 820 causesflywheel 722 to pivot in the direction of arrow, Z, as shown in the FIG.34, to decrease the stroke of the pistons. Moving pressure plate 820 by0.75″ decreases the compression ratio from about 12:1 to about 6:1.

Pressure plate 820 is supported by three or more screws 832. Each screwhas a gear head 840 which interfaces with a gear 842 on pressure plate820 such that rotation of screw 832 causes rotation of pressure plate820 and thus rotation of the remaining screws to insure that thepressure plate is adequately supported. To ensure contact between roller822 and pressure plate 820, a piston 850 is provided which biasesflywheel 722 in the direction opposite to arrow, Z.

Referring to FIG. 30, if two cylinders not spaced 180° apart (as viewedfrom the end) or more than two cylinders are employed in piston assembly300, the ends of pins 312, 314 coupled to joints 306, 308 will undergo aFIG. 8 motion. FIG. 30 shows the FIG. 8 motion of a piston assemblyhaving four double ended pistons. Two of the pistons are arranged flatas shown in FIG. 22 (and do not undergo the FIG. 8 motion), and theother two pistons are arranged equally spaced between the flat pistons(and are thus positioned to undergo the largest FIG. 8 deviationpossible). The amount that the pins connected to the second set ofpistons deviate from a straight line (y axis of FIG. 30) is determinedby the swing angle (mast angle) of the drive arm and the distance thepin is from the central pivot point 352 (x axis of FIG. 30).

In a four cylinder version where the pins through the piston pivotassembly of each of the four double ended pistons are set at 45° fromthe axis of the central pivot, the figure eight motion is equal at eachpiston pin. Movement in the piston pivot bushing is provided where thefigure eight motion occurs to prevent binding.

When piston assembly 300 is configured for use, e.g., as a dieselengines, extra support can be provided at the attachment of pins 312,314 to transition arm 310 to account for the higher compression ofdiesel engines as compared to spark ignition engines. Referring to FIG.31, support 550 is bolted to transition arm 310 with bolts 551 andincludes an opening 552 for receiving end 554 of the pin.

Engines according to the invention can be used to directly applycombustion pressures to pump pistons. Referring to FIGS. 32 and 32 a, afour cylinder, two stroke cycle engine 600 (each of the four pistons 602fires once in one revolution) applies combustion pressure to each offour pump pistons 604. Each pump piston 604 is attached to the outputside 606 of a corresponding piston cylinder 608. Pump pistons 604 extendinto a pump head 610.

A transition arm 620 is connected to each cylinder 608 and to a flywheel622, as described above. An auxiliary output shaft 624 is connected toflywheel 622 to rotate with the flywheel, also as described above.

The engine is a two stroke cycle engine because every stroke of a piston602 (as piston 602 travels to the right as viewed in FIG. 32) must be apower stroke. The number of engine cylinders is selected as required bythe pump. The pump can be a fluid or gas pump. In use as a multi-stageair compressor, each pump piston 606 can be a different diameter. Nobearing loads are generated by the pumping function (for single actingpump compressor cylinders), and therefore, no friction is introducedother than that generated by the pump pistons themselves.

Referring to FIGS. 38-38B, an engine 1010 having vibration cancelingcharacteristics and being particularly suited for use in gas compressionincludes two assemblies 1012, 1014 mounted back-to-back and 180° out ofphase. Engine 1010 includes a central engine section 1016 and outercompressor sections 1018, 1020. Engine section 1016 includes, e.g., sixdouble acting cylinders 1022, each housing a pair of piston 1024, 1026.A power stroke occurs when a center section 1028 of cylinder 1022 isfired, moving pistons 1024, 1026 away from each other. The opposedmovement of the pistons results in vibration canceling.

Outer compression section 1018 includes two compressor cylinders 1030and outer compression section 1020 includes two compressor cylinders1032, though there could be up to six compressor cylinders in eachcompression section. Compression cylinders 1030 each house a compressionpiston 1034 mounted to one of pistons 1024 by a rod 1036, andcompression cylinders 1032 each house a compression piston 1038 mountedto one of pistons 1026 by a rod 1040. Compression cylinders 1030, 1032are mounted to opposite piston pairs such that the forces cancelminimizing vibration forces which would otherwise be transmitted intomounting 1041.

Pistons 1024 are coupled by a transition arm 1042, and pistons 1026 arecoupled by a transition arm 1044, as described above. Transition arm1042 includes a drive arm 1046 extending into a flywheel 1048, andtransition arm 1044 includes a drive arm 1050 extending into a flywheel1052, as described above. Flywheel 1048 is joined to flywheel 1052 by acoupling arm 1054 to rotate in synchronization therewith. Flywheels1048, 1052 are mounted on bearings 1056. Flywheel 1048 includes a bevelgear 1058 which drives a shaft 1060 for the engine starter, oil pump anddistributor for ignition, not shown.

Engine 1010 is, e.g., a two stroke natural gas engine having ports (notshown) in central section 1028 of cylinders 1022 and a turbocharger (notshown) which provides intake air under pressure for purging cylinders1022. Alternatively, engine 1010 is gasoline or diesel powered.

The stroke of pistons 1024, 1026 can be varied by moving both flywheels1048, 1052 such that the stroke of the engine pistons and the compressorpistons are adjusted equally reducing or increasing the engine power asthe pumping power requirement reduces or increases, respectively.

The vibration canceling characteristics of the back-to-back relationshipof assemblies 1012, 1014 can be advantageously employed in a compressoronly system and an engine only system.

Counterweights can be employed to limit vibration of the pistonassembly. Referring to FIG. 39, an engine 1100 includes counterweights1114 and 1116. Counterweight 1114 is mounted to rotate with a rotatablemember 1108, e.g., a flywheel, connected to drive arm 320 extending fromtransition arm 310. Counterweight 1116 is mounted to lower shaft 608 torotate with shaft 608.

Movement of the double ended pistons 306, 308 is translated bytransition arm 310 into rotary motion of member 1108 and counterweight1114. The rotation of member 1108 causes main drive shaft 408 to rotate.Mounted to shaft 408 is a first gear 1110 which rotates with shaft 408.Mounted to lower shaft 608 is a second gear 1112 driven by gear 1110 torotate at the same speed as gear 1110 and in the opposite direction tothe direction of rotation of gear 1110. The rotation of gear 1112 causesrotation of shaft 608 and thus rotation of counterweight 1116.

As viewed from the left in FIG. 39, counterweight 1114 rotates clockwise(arrow 1118) and counterweight 1116 rotates counterclockwise (arrow1120). Counterweights 1114 and 1116 are mounted 180 degrees out of phasesuch that when counterweight 1114 is above shaft 408, counterweight 1116is below shaft 608. A quarter turn results in both counterweights 1114,1116 being to the right of their respective shafts (see FIG. 40). Afteranother quarter turn, counterweight 1114 is below shaft 408 andcounterweight 1116 is above shaft 608. Another quarter turn and bothcounterweights are to the left of their respective shafts.

Referring to FIG. 40, movement of pistons 306, 308 along the Y axis, inthe plane of the XY axes, creates a moment about the Z axis, M_(zy).When counterweights 1114, 1116 are positioned as shown in FIG. 40, thecentrifugal forces due to their rotation creates forces, F_(x1) andF_(x2), respectively, parallel to the X axis. These forces act togetherto create a moment about the Z axis, M_(zx). The weight ofcounterweights 1114, 1116 is selected such that M_(zx) substantiallycancels M_(zy).

When pistons 306, 308 are centered on the X axis (FIG. 39) there are noforces acting on pistons 306, 308, and thus no moment about the Z axis.In this position, counterweights 1114, 1116 are in opposite positions asshown in FIG. 39 and the moments created about the X axis by thecentrifugal forces on the counterweights cancel. The same is true after180 degrees of rotation of shafts 408 and 608, when the pistons areagain centered on the X axis and the counterweight 1114 is below shaft408 and counterweight 1116 is above shaft 608.

Between the quarter positions, the moments about the X axis due torotation of counterweights 1114 and 1116 cancel, and the moments aboutthe Z axis due to rotation of counterweights 1114 and 1116 add.

Counterweight 1114 also accounts for moments produced by drive arm 320.

In other piston configurations, for example where pistons 306, 308 donot lie on a common plane or where there are more than two pistons,counterweight 1116 is not necessary because at no time is there nomoment about the Z axis requiring the moment created by counterweight1114 to be cancelled.

One moment not accounted for in the counterbalancing technique of FIGS.39 and 40 a moment about axis Y, M_(yx), produced by rotation ofcounterweight 1116. Another embodiment of a counterbalancing techniquewhich accounts for all moments is shown in FIG. 41. Here, acounterweight 1114 a mounted to rotating member 1108 is sized to onlybalance transition arm 310. Counterweights 1130, 1132 are provided tocounterbalance the inertial forces of double-ended pistons 306, 308.

Counterweight 1130 is mounted to gear 1110 to rotate clockwise with gear1110. Counterweight 1132 is driven through a pulley system 1134 torotate counterclockwise. Pulley system 1134 includes a pulley 1136mounted to rotate with shaft 608, and a chain or timing belt 1138.Counterweight 1132 is mounted to shaft 408 by a pulley 1140 and bearing1142. Counterclockwise rotation of pulley 1136 causes counterclockwiserotation of chain or belt 1138 and counterclockwise rotation ofcounterweight 1132.

Referring to FIG. 42, as discussed above, movement of pistons 306, 308along the Y axis, in the plane of the XY axes, creates a moment aboutthe Z axis, M_(zy). When counterweights 1130, 1132 are positioned asshown in FIG. 42, the centrifugal forces due to their rotation createsforces, F_(x3) and F_(x4), respectively, in the same direction along theX axis. These forces act together to create a moment about the Z axis,M_(zx). The weight of counterweights 1130, 1132 is selected such thatM_(zx) substantially cancels M_(zy).

When pistons 306, 308 are centered on the X axis (FIG. 41) there are noforces acting on pistons 306, 308, and thus no moment about the Z axis.In this position, counterweights 1130, 1132 are in opposite positions asshown in FIG. 41 and the moments created about the X axis by thecentrifugal forces on the counterweights cancel. The same is true after180 degrees of rotation of shafts 408 and 608, when the pistons areagain centered on the X axis and the counterweight 1130 is below shaft408 and counterweight 1132 is above shaft 408.

Between the quarter positions, the moments about the X axis due torotation of counterweights 1130 and 1132 cancel, and the moments aboutthe Z axis due to rotation of counterweights 1130 and 1132 add. Sincecounterweights 1130 and 1132 both rotate about the Y axis, there is nomoment M_(yx) created about axis Y.

Counterweights 1130, 1132 are positioned close together along the Y axisto provide near equal moments about the Z axis. The weights ofcounterweights 1130, 1132 can be slightly different to account for theirvarying location along the Y axis so that each counterweight generatesthe same moment about the center of gravity of the engine.

Counterweights 1130, 1132, in addition to providing the desired momentsabout the Z axis, create undesirable lateral forces directedperpendicular to the Y-axis (in the direction of the X axis), which acton the U-joint or other mount supporting transition arm 310. Whencounterweights 1130, 1132 are positioned as shown in FIG. 41, this doesnot occur because the upward force, F_(u), and the downward force,F_(d), cancel. But, when counterweights 1130, 1132 are positioned otherthan as shown in FIG. 41 or 180° from that position, this force isapplied to the mount. For example, as shown in FIG. 42, forces F_(x3)and F_(x4) create a side force, F_(s), along the X axis. One techniqueof incorporating counterbalances which provide the desired moments aboutthe Z axis without creating the undesirable forces on the mount is shownin FIG. 43.

Referring to FIG. 43, a second pair of counterweights 1150, 1152 areprovided. Counterweights 1130 and 1152 are mounted to shaft 408 torotate clockwise with shaft 408. Counterweights 1132 and 1150 aremounted to a cylinder 1154 surrounding shaft 408 which is driven throughpulley system 1134 to rotate counterclockwise. Counterweights 1130, 1152extend from opposite sides of shaft 408 (counterweight 1130 beingdirected downward in FIG. 43, and counterweight 1152 being directedupward), and counterweights 1132, 1150 extend from opposite sides ofcylinder 1154 (counterweight 1132 being directed upward, andcounterweight 1150 being directed downward). Counterweights 1130, 1150are aligned on the same side of shaft 408, and counterweights 1132, 1152are aligned on the opposite side of shaft 408.

Referring to FIG. 44, with counterweights 1130, 1132, 1150, 1152positioned as shown, the centrifugal forces due to the rotation ofcounterweights 1130, 1132 creates forces, F_(x3) and F_(x4),respectively, in the same direction in the X axis, and the centrifugalforces due to the rotation of counterweights 1150, 1152 creates forces,F_(x5) and F_(x6), respectively, in the opposite direction in the Xaxis. Since F_(x3) and F_(x4) are equal and opposite to F_(x5) andF_(x6), these forces cancel such that no undesirable lateral forces areapplied to the transition arm mount.

In addition, as discussed above, movement of pistons 306, 308 in thedirection of the Y axis, in the plane of the XY axes, creates a momentabout the Z axis, M_(zy). Since counterweights 1130, 1132, 1150, 1152are substantially the same weight, and counterweights 1150, 1152 arelocated further from the Z axis than counterweights 1130, 1132, themoment created by counterweights 1150, 1152 is larger than the momentcreated by counterweights 1130, 1132 such that these forces act togetherto create a moment about the Z axis, M_(zx), which acts in the oppositedirection to M_(zy). The weight of counterweights 1130, 1132, 1150, 1152is selected such that M_(zx) substantially cancels M_(zy).

When pistons 306, 308 are centered on the X axis (FIG. 43), there is nomoment about the Z axis. In this position, counterweights 1130, 1132 areoppositely directed and counterweights 1150, 1152 are oppositelydirected such that the moments created about the X axis by thecentrifugal forces on the counterweights cancel. Likewise, the forcescreated perpendicular to the Y axis, F_(u) and F_(d), cancel. The sameis true after 180 degrees of rotation of shafts 408 and 608, when thepistons are again centered on the X axis.

Counterweight 1130 can be incorporated into flywheel 1108, thuseliminating one of the counterweights.

Referring to FIG. 45, another configuration for balancing a pistonengine having two double ended pistons 306, 308 180° apart around the Yaxis includes two members 1160, 1162, which each simulate a double endedpiston, and two counterweights 1164, 1166. Members 1160, 1162 are 180°apart and equally spaced between pistons 306, 308. Counterweights 1164,1166 extend from opposite sides of shaft 408, with counterweight 1166being spaced further from the Z axis than counterweight 1164. Hereagain, counterweight 1114 a mounted to rotating member 1108 is sized toonly balance transition arm 310.

Movement of members 1160, 1162 along the Y axis, in the plane of the YZaxis, creates a moment about the X axis, My. When counterweights 1164,1166 are positioned as shown in FIG. 45, the centrifugal forces due tothe rotation of counterweights 1164, 1166 creates forces, F_(u) andF_(d), respectively, in opposite directions along the Z axis. Sincecounterweight 1166 is located further from the Z axis than counterweight1164, the moment created by counterweight 1166 is larger than the momentcreated by counterweight 1164 such that these forces act together tocreate a moment about the X axis, M_(xz), which acts in the oppositedirection to M The weight of counterweights 1164, 1166 is selected suchthat M_(xz) substantially cancels M_(xy).

In addition, since the forces, F_(u) and F_(d), are oppositely directed,these forces cancel such that no undesirable lateral forces are appliedto the transition arm mount.

Referring to FIG. 46, movement of pistons 306, 308 along the Y axis, inthe plane of the XY axes, creates a moment about the Z axis, M_(zy).When counterweights 1164, 1166 are positioned as shown in FIG. 45, thecentrifugal forces due to the rotation of counterweights 1164, 1166creates forces, F_(x7) and F_(x8), respectively, in opposite directionsalong the X axis. These forces act together to create a moment about theZ axis, M_(zx), which acts in the opposite direction to M_(zy). Theweight of counterweights 1164, 1166 is selected such that M_(zx)substantially cancels M_(zy).

In addition, since the forces perpendicular to Y axis, F_(x7) andF_(x8), are oppositely directed, these forces cancel such that noundesirable lateral forces are applied to the transition arm mount.

Counterweight 1164 can be incorporated into flywheel 1108 thuseliminating one of the counterweights.

The piston engine can include any number of pistons and simulated pistoncounterweights to provide the desired balancing, e.g., a three pistonengine can be formed by replacing one of the simulated pistoncounterweights in FIG. 43 with a piston, and a two piston engine can beformed with two pistons and one simulated piston counterweight equallyspaced about the transition arm.

If the compression ratio of the pistons is changed, the position of thecounterweights along shaft 408 is adjusted to compensate for theresulting change in moments.

Another undesirable force that can be advantageously reduced oreliminated is a thrust load applied by transition arm 310 to flywheel1108 that is generated by the circular travel of transition arm 310.Referring to FIG. 47, the circular travel of transition arm 310generates a centrifugal force, C₁, which is transmitted through nose pin320 and sleeve bearing 376 to flywheel 1108. Although counterweight 1114produces a centrifugal force in the direction of arrow 2010 whichbalances force C₁, at the 15° angle of nose pin 320, a lateral thrust,T, of 26% of the centrifugal force, C₁, is also produced. The thrust canbe controlled by placing thrust bearings or tapered roller bearings 2040on shaft 408.

To reduce the load on bearings 2040, and thus increase the life of thebearings, as shown in FIG. 48, nose pin 320 a is spherically shaped withflywheel 1108 a defining a spherical opening 2012 for receiving thespherical nose pin 320 a. Because of the spherical shapes, no lateralthrust is produced by the centrifugal force, C₁.

FIG. 49 shows another method of preventing the application of a thrustload to the tansition arm. Here, a counterbalance element 2014, ratherthan being an integral component of the flywheel 1108 b, is attached tothe flywheel by bolts 2016. The nose pin 320 b includes a sphericalportion 2018 and a cylindrical portion 2020. Counterbalance element 2014defines a spherical opening 2022 for receiving spherical portion 2018 ofnose pin 320 b. Cylindrical portion 2020 of nose pin 320 b is receivedwithin a sleeve bearing 2024 in a cylindrical opening 2026 defined byflywheel 1108 b. Because of the spherical shapes, no lateral thrust isproduced by the centrifugal force, C₁.

Counterbalance element 2014 is not rigidly held to flywheel 1108 b sothat there is no restraint to the full force of the counterweight beingapplied to the spherical joint to cancel the centrifugal force createdby the circular travel of transition arm 310. For example, a clearancespace 2030 is provided in the screw holes 2032 defined in counterbalanceelement 2014 for receiving bolts 2016.

One advantage of this embodiment over that of FIG. 48 is that the lifeexpectancy of a cylindrical joint with a sleeve bearing coupling thetransition arm to the flywheel is longer than that of the sphericaljoint of FIG. 48 coupling the transition arm to the flywheel.

Referring to FIG. 50, a hydraulic pump 2110 includes a stationaryhousing 2112 defining a chamber 2114, and a rotating drum or cylinder2116 located within chamber 2114. Cylinder 2116 includes first andsecond halves 2116 a, 2116 b defining a plurality of piston cavities2117. Each cavity 2117 is formed by a pair of aligned channels 2118,2120 joined by an enlarged region 2122 defined between cylinder halves2116 a, 2116 b. Located within each cavity 2117 is a double ended piston2124, here six pistons being shown, though fewer or more pistons can beemployed depending upon the application. Each double ended piston ismounted to a transition arm 2126 by a joint 2128, as described above.Transition arm 2126 is supported on a universal joint 2130 mounted tocylinder 2116 such that pistons 2124 and transition arm 2126 rotate withcylinder 2116.

The angle, γ, of transition arm 2126 relative to longitudinal axis, A,of pump 2110 is adjustable to reduce or increase the output from pump2110. Pump 2110 includes an adjustment mechanism 2140 for adjusting andsetting angle, γ. Adjustment mechanism 2140 includes an arm 2142 mountedto a stationary support 2144 to pivot about a point 2146. An end 2148 ofarm 2142 is coupled to a first end 2152 of a control rod 2150 by a pin2154. Arm 2142 defines an elongated hole 2155 which receives pin 2154and allows for radial movement of arm 2142 relative to control rod 2150when arm 2142 is rotated about pivot point 2146. A second end 2156 ofrod 2150 has laterally facing gear teeth 2158. Gear teeth 2158 mate withgear teeth 2160 on a link 2162 mounted to pivot about a point 2164. Anend 2166 of link 2162 is coupled to transition arm 2126 at a pivot joint2168. Transition arm nose pin 2126 a is supported by a cylindrical pivotpin 370 (not shown) and sleeve bearing 376 (not shown), as describedabove with reference to FIGS. 25-25 b, such that transition arm 2126 isfree to rotate relative to adjustment mechanism 2140.

Angle, γ, is adjusted as follows. Arm 2142 is rotated about pivot point2146 (arrow, B). This results in linear movement of rod 2150 (arrow, C).Because of the mating of gear teeth 2158 and 2160, the linear movementof rod 2150 causes link 2162 to rotate about pivot point 2164 (arrow,D), thus changing angle, γ. After the desired angle has been obtained,the angle is set by fixing arm 2142 using an actuator (not shown)connected to end 2142 a of arm 2142.

Due to the fixed angle of transition arm 2126 (after adjustment to thedesired angle), and the coupling of transition arm 2126 to pistons 2124,as the transition arm rotates, pistons 2124 reciprocate within cavities2117. One rotation of cylinder 2116 causes each piston 2124 to completeone pump and one intake stroke.

Referring also to FIG. 51, pump 2110 includes a face valve 2170 whichcontrols the flow of fluid, e.g., pressurized hydraulic oil, in pump2110. On the intake strokes, fluid is delivered to channels 2118 and2120 through an inlet 2172 in face valve 2170. Inlet 2172 is in fluidcommunication with an inlet port 2174. Inlet port 2174 includes a firstsection 2174 a that delivers fluid to channels 2120, and a secondsection 2174 b that delivers fluid to channels 2118. First section 2174a is located radially outward of second section 2174 b. On the pumpstrokes, fluid is expelled from channels 2118 and 2120 through an outlet2176 in face valve 2170. Outlet 2176 is in fluid communication with anoutlet port 2178. Outlet port 2178 includes a first section 2178 a viawhich fluid expelled from channels 2120 is delivered to outlet 2176, anda second section 2178 b via which fluid expelled from channels 2118 isdelivered to outlet 2176. First section 2178 a is located radiallyoutward of second section 2178 b.

Referring also to FIG. 52, cylinder 2116 defines six flow channels 2180through which fluid travels to and from channels 2120. Flow channels2180 are radially aligned with port sections 2174 a and 2178 b; andchannels 2118 are radially aligned with port sections 2174 b and 2178 b.When a first end 2124 a of piston 2124 is on the intake stroke and asecond end 2124 b of piston 2124 is on the pump stroke, cylinder 2116 isrotationally aligned relative to stationary face valve 2170 such thatthe respective channel 2118 at first end 2124 a of piston 2124 isaligned with inlet port section 2174 b, and the respective flow channel2180 leading to a respective channel 2120 at second end 2124 b of piston2124 is aligned with outlet port section 2178 a.

Cylinder 2116 further defines six holes 2182 for receiving connectingbolts (not shown) that hold the two halves 2116 a, 2116 b of cylinder2116 together. Cylinder 2116 is biased toward face valve 2170 tomaintain a valve seal by spring loading. Referring to FIG. 53, a faceplate 2190 defining outer slots 2192 a and inner slots 2192 b ispositioned between stationary face valve 2170 and rotating cylinder 2116to act as a bearing surface. Outer slots 2192 a are radially alignedwith port sections 2174 a and 2178 a, and inner slots 2192 b areradially aligned with port sections 2174 b and 2178 b.

Referring to FIG. 54, a pump or compressor assembly 2210 for varying thestroke of pistons 2212, e.g., a pump with single ended pistons having apiston 2212 a at one end and a guide rod 2212 b at the opposite end, hasthe ability to vary the stroke of pistons 2212 down to zero stroke andthe capability of handling torque loads as high as a fixed strokemechanism. Assembly 2210 is shown with three pistons, though two or morepistons can be employed. Assembly 2210 includes a transition arm 2214coupled to pistons 2212 by any of the methods described above.Transition arm 2214 includes a nose pin 2216 coupled to a rotatableflywheel 2218. The rotation of flywheel 2218 and the linear movement ofpistons 2212 are coupled by transition arm 2214 as described above.

The stroke of pistons 2212, and thus the output volume of assembly 2210,is adjusted by changing the angle, δ, of nose pin 2216 relative toassembly axis, A. Angle, δ, is changed by rotating transition arm 2214,arrow, E, about axis, F, of support 2220, e.g., a universal joint.Flywheel 2218 defines an arced channel 2220 housing a bearing block2222. Bearing block 2222 is slidable within channel 2220 to change theangle, δ, while the cantilever length, L, remains constant andpreferably as short as possible for carrying high loads. Within bearingblock 2222 is mounted a bearing 2224, e.g., a sleeve or rolling bearing,which receives nose pin 2216. Bearing block 2222 has a gear toothedsurface 2226, for reasons described below.

Referring also to FIG. 55, to slide bearing block 2222 within channel2220, a control rod 2230, which passes through and is guided by a guidebushing 2231 within cylindrical opening 2232 in main drive shaft 2234and rotates with drive shaft 2234, includes a toothed surface 2236 whichengages a pinion gear 2238. Pinion gear 2238 is coupled to gear toothedsurface 2226 of bearing block 2222, and is mounted in bushings 2240.Axial movement of control rod 2230, in the direction of arrow, B, causespinion gear 2238 to rotate, arrow, C. Rotation of pinion gear 2238causes bearing block 2222 to slide in channel 2220, arrow D,circumferentially about a circle centered on U-joint axis, F, thuschanging angle, δ. The stroke of pistons 2212 is thus adjusted whileflywheel 2218 remains axially stationary (along the direction of arrow,B).

Referring to FIG. 57, to counterbalance the movement of transition arm2214 and bearing block 2222, a movable balance member 2410 is coupled toa control rod 2230 a. Control rod 2230 a includes linear toothed surface2236 in a first end region 2412 of the control rod (as in control rod2230 of FIGS. 54 and 55), as well as a second linear toothed surface2414 at an opposite end region 2416 of control rod 2230 a. Toothedsurface 2236 mates with bearing block 2222, as described above. Toothedsurface 2414 mates with a gear 2418, and gear 2418 mates with a toothedsurface 2420 of balance member 2410. Linear movement of control rod 2230a, arrow, b, thus causes gear 2418 to rotate, arrow, c, and balancemember 2410 to translate, arrow, d. Flywheel 2218 and gears 2238 and2418 are balanced as a unit about axis, F. Transition arm 2214 andbalance member 2410 are both balanced about axis, F, when the pistonsare at zero-stroke.

When control rod 2230 a is moved to the right, as viewed in FIG. 57,gear 2238 rotates counter-clockwise, and bearing block 2222 movesdownward along a slight arc, shortening the stroke of the pistons.Simultaneously, gear 2418 rotates counter-clockwise, and balance member2410 moves upward in a substantially opposite direction to the directionof movement of bearing block 2222. While there is a slight variation inthe movement of bearing block 2222 and balance member 2410 (bearingblock 2222 undergoes radial motion while balance member 2410 undergoeslinear motion), the balancing obtained significantly reduces potentialvibration of the assembly.

Referring to FIG. 58, a dual capacity compressor 3010, for example, agas refrigerant compressor, is shown that is particularly useful inapplications in which compressor capacity is preferably varied toconserve energy, such as in home refrigerators. Compressor 3010 includesfirst and second piston assemblies 3012 mounted circumferentially abouta transition arm 3014. Transition arm 3014 is mounted to a universaljoint 3016, and drive pins 3018 couple transition arm 3014 to pistonassemblies 3012 via piston joint assemblies 3020. The motion oftransition arm 3014 causes linear motion of piston assemblies 3012, asdescribed above.

Each piston assembly 3012 includes a piston 3024 and an opposed guiderod 3026. Compressor 3010 includes a case 3030 defining cylinders 3032within which piston assemblies 3012 are mounted. Each cylinders 3032 hasan end wall 3034. Guide rods 3026 each ride within a bearing 3036positioned in a respective cylinder 3032.

Compressor 3010 includes a linear, stroke/clearance control mechanism3040 that maintains the clearance distance, d, between an end face 3042of piston 3024 and end wall 3034 at the top of the piston strokesubstantially constant as the stroke of piston 3024 is changed.Mechanism 3040 includes a stroke control lever 3050, a link rod 3052,and a U-joint control lever 3054. Lever 3050 is connected to rod 3052 ata pivot joint 3050 a, and lever 3054 is connected to rod 3052 at pivotjoint 3054 a. Stroke control lever 3050 is connected to a rotatingstroke control arm 3056 by a bearing 3056 a mounted between thrustwashers 3056 b, and a pivot joint 3050 b. Lever 3050 is grounded to case3030 by a pivot joint 3050 c. U-joint control lever 3054 is connected toan arm 3062 to which U-joint 3016 is mounted by a pivot joint 3054 b.Lever 3054 is grounded to case 3030 by a pivot joint 3054 c. The length,L1, of lever 3050 between joints 3050 b and 3050 c is, for example, 2.5inches; the length, L2, of lever 3050 between joints 3050 c and 3050 ais, for example, 2.5 inches; the length, L3, of lever 3054 betweenjoints 3054 b and 3054 c is, for example, 1.5 inches; the length, L4, oflever 3054 between joints 3054 b and 3054 a is, for example, 3.5 inches;and the length, L5, of link rod 3052 between joints 3050 a and 3054 ais, for example, 16 inches.

Stroke control arm 3056 has a flywheel 3058 that slides relative to anose pin 3060 of transition arm 3014. Arm 3062 includes a spline 3066received within a slot 3068 in case 3030 to prevent rotation of arm 3062and U-joint 3016 relative to case 3030. Moving the axial position offlywheel 3058, arrow, A, relative to nose pin 3060, changes the coneangle, θ, of transition arm 3014, and thus the stroke of pistonassemblies 3012. Moving U-joint 3016, arrow, B, moves the axial positionof piston assemblies 3012 within cylinders 3032, arrow, C, thusadjusting the top clearance volume, i.e., the distance, d, betweenpiston end face 3042 and end wall 3034.

Mechanism 3040 thus couples the motion of the U-joint and the strokecontrol. The relationship between the two motions is linear or nearlyso, since it is maintained by two levers 3050, 3054 and one pushrod3052. The relationship is inverse and roughly four to one, so that fourunits of movement of the stroke arm 3056 correspond to one unit ofmovement of the U-joint arm 3062. The motion of U-joint 3016 equals thedistance, d₁, between the central axis, W, and the piston axis, X, timesthe tangent of cone angle, θ. The motion of stroke arm 3056 is thedistance, d₂, between central axis, W, and an axis, Y, parallel to axis,W, (defined by a center, Z, of nose pin 3060) divided by the tangent ofcone angle, θ, plus the motion of U-joint 3016. In the example of FIG.1, d₁ is 2 inches, and d₂ is 0.5 inches.

The piston stroke and top clearance are simultaneously adjusted byapplying a force, F, to link rod 3052. When link rod 3052 is moved tothe right, as viewed in FIG. 58, flywheel 3058 moves to the left by theaction of stroke control lever 3050, decreasing angle, θ, and thusdecreasing the piston stroke. If the position of U-joint 3016 were notalso adjusted, the decrease in piston stroke would cause an increase intop clearance distance, d. However, when link rod 3052 is moved to theright, U-joint 3016 moves to the right by the action of U-joint controllever 3054, which moves piston end face 3042 closer to end wall 3034,thus maintaining top clearance distance, d, substantially constant.

To obtain a pumping efficiency of close to 100%, it is desirable to havetop clearance distance, d, as close to zero as possible withoutcontacting piston end face 3042 against end wall 3034. For example, asshown in FIG. 59, for the linear compensation provided by mechanism 3040of FIG. 58, as the cone angle, θ, increases from 8 to 24 degrees, thestroke increases, and the clearance distance, d, ranges between zeromils and 113 mils. The highest efficiency is seen at cone angles of 8and 24 degrees where the clearance distance is essentially zero.

The ratio, K, of the axial motion of flywheel arm 3056 to the axialmotion of U-joint 3016 can be adjusted to change the cone angle, andthus the stroke, at which the clearance distance is essentially zero.For example, in FIG. 58, the ratio, K, is −0.22. By changing the lengthof stroke control lever 3050, link rod 3052, or U-joint control lever3054 the ratio, K, can be changed.

The clearance distance obtained as the stroke of the pistons is adjustedcan be further modified by incorporating second-order compensation.Referring to FIG. 60, a continuously variable capacity compressor 3010 aincludes a non-linear, stroke/clearance control mechanism 3040 a. Inmechanism 3040 a, linkage rod 3052 a is coupled to stroke control lever3051 a by a non-linear link 3070. Link 3070 includes a short link 3072and a triangular grounded link 3074. Link 3072 is connected to strokecontrol lever 3051 a by a pivot joint 3072 a, and to link 3074 by apivot joint 3072 b. Link 3074 is connected to linkage rod 3052 a by apivot joint 3074 a, and is grounded to case 3030 by a pivot joint 3074b. Lever 3055 a is connected to rod 3052 a at pivot joint 3057 a. Strokecontrol lever 3051 a is connected to a rotating stroke control arm 3056a and U-joint control lever 3055 a is connected to an arm 3062 a asdescribed above with reference to FIG. 58. Links 3072 and 3074 create asecond order term in the transfer function between stroke arm movementand U-joint movement. The transfer function can be modified by, forexample, changing the length, L₆, of short link 3072 or the angle, α, oftriangular link 3074, to obtain a desired relationship.

The resulting curve for the non-linear mechanism of FIG. 60 is alsoshown in FIG. 59. Zero clearance occurs at cone angles of 10.5 and 24degrees, with a maximum clearance distance, d, of 23 mils occurring at acone angle of 17 degrees. Thus, the clearance is maintained below 23mils for a stroke range of 330 to 1000 mils, providing efficientoperation over the entire stroke range. The ratio of clearance to strokedefines the efficiency, with a low ratio corresponding to highefficiency. For the non-linear mechanism, this ratio is less than 3%over the entire stroke range. FIG. 59 also includes a curve of theclearance, d, when no compensation mechanism is employed.

The ability to vary the capacity of the compressor using the mechanismsof FIGS. 58 and 60 allows the compressor to be started at minimumcapacity and then be ramped up. This allows for a low starting torque.The non-linear mechanism also exhibits unloading at minimum stroke, ascan be seen by the rise in clearance at 8 degrees and a stroke of 316mils to 58 mils, thus limiting the gas compression forces and thereforethe starting load placed on the motor.

Referring to FIG. 61, an integral motor/compressor 3100 includes ahousing 3102 defining a motor section 3104 and a compressor section3106. Motor section 3104 houses a motor 3110 and a drive arm 3112. Motor3110 includes a stator 3114 and a rotor 3116. Drive arm 3112 is mountedto rotate with rotor 3116 and to slide axially, arrow, D, relative torotor 3116. To this end, drive arm 3112 has a spline 3118 receivedwithin a slot 3120 in rotor 3116. Mounted to an end 3122 of drive arm3112 is a flywheel 3124 located in compressor section 3106. Also withincompressor section 3106 are a transition arm 3130 supported by a U-joint3132 and pistons 3134. The configuration of transition arm 3130, U-joint3132 and pistons 3134 are as described above. Transition arm 3130includes a nose pin 3136 slidably received within an opening 3138defined by flywheel 3124.

As discussed above, axial movement of drive arm 3112 changes the strokeof pistons 3134. Housing 3102 defines a chamber 3140 in which a piston3142 is located. Piston 3142 is coupled to drive arm 3112 by a controllink 3144. Piston 3142 is attached to control link 3144 at a pivot 3144a. Link 3144 pivots about a fixed pivot 3144 b and is a attached to acollar 3145 coupled to drive arm 3112 at a pivot 3144 c, such thatlinear motion of piston 3142 causes linear motion of drive arm 3112 tochange the stroke of pistons 3134. Drive arm 3112 rotates within collar3145, and collar 3145 acts against a thrust washer 3147 that rotateswith drive arm 3112 and absorbs the force of collar 3145 pushing againstdrive arm 3112. Between an end face 3146 of piston 3142 and an end wall3148 of housing 3102 is a gas chamber 3150. By adjusting the gaspressure in gas chamber 3150, the axial position of drive arm 3112 canbe changed, thus changing the stroke of pistons 3134.

Referring to FIG. 62, a stroke/clearance control mechanism 3040 b thatmaintains the clearance distance, d, at the top of the piston strokesubstantially constant as the stroke of the pistons is changed is shownincorporated with integral/motor compressor 3100. As discussed abovewith reference to FIG. 58, mechanism 3040 b includes a stroke controllever 3051 b, a link rod 3052 b, and a U-joint control lever 3055 b.Mechanism 3040 b functions as described above with reference to FIG. 58,with the clearance distance substantially zero at two points of thepiston stroke. The mechanism of FIG. 60 can also be incorporated intointegral/motor compressor 3100.

Compressors 3010 and 3010 a and integral motor/compressor 3100 caninclude more than two piston assemblies. The stroke/clearance controlmechanisms described above can used to vary the top clearance of aninternal combustion engine so that the compression ratio remainssubstantially constant over a wide range of displacements, that is, theclearance distance, d, remains substantially the same percentage of thestroke as the stroke is varied. Any other desirable relationship canalso be created by adjusting the shapes and or lengths of the variouslevers.

Referring to FIGS. 63 and 64, a metering pump 10 a for delivering knownamounts of various fluids includes a plurality of piston cylinders 12 a,two, three or more cylinders, radially disposed about a centralactuating mechanism 14 a. Housed within each cylinder 12 a is a piston16 a and a guide rod 16 b supported by a guide bushing or sleeve bearing16 c. Cylinders 12 a each include a fluid inlet 18 a for deliveringfluid into cylinder 12 a, and a fluid outlet 20 a for delivering meteredfluid. At each of inlet 18 a and outlet 20 a a spring-loaded, ball checkvalve 22 a is positioned to provide one-way fluid flow, though othertypes of valves can be used. Actuating mechanism 14 a includes atransition arm 25 a coupled to a stationary support 26 a by, e.g., aU-joint. Transition arm 24 a includes a plurality of arms 30 a, eachcoupled to one of the cylinders 12 a by a joint 71 a, and an arm 34 acoupled to a rotary member 36 a. Various embodiments of actuatingmechanism 14 a and joint 71 a have been described above.

The working volume and thus the output of cylinders 12 a preferablydiffer, e.g., by a proportional relationship. This feature isparticularly applicable where it is desired that the portions of variousfluids to be mixed remain constant once determined and set. Meteringpump 10 a provides precise adjustment and accurate and repeatableperformance as a precision positive displacement device.

The working volume of each cylinder, and thus the volume of meteredfluid, is defined by the stroke of piston 16 a and the inner diameter,d, of cylinder 12 a. For each cylinder/piston combination, the diameterof the cylinder and/or the stroke of the piston can differ, permittingthe pumping of different fluids in different but exact quantities. Forexample, to mix five different liquids, each liquid being a differentpercentage of the mixed fluid, five cylinders 12 a are arranged aboutactuating mechanism 14 a with each cylinder having a different diameter,d1-d5, such that equal strokes deliver the desired mix percentages fromeach cylinder. Alternatively, or in addition, the distance, D, ofcylinders 12 a from a central pivot 40 a of transition arm 24 a (asmeasured by the distance between central pivot 40 a and a center 28 a ofjoint 71 a) differ to provide different strokes. For example, coarsevalues for each fluid is determined by the cylinder diameter, and fineadjustment is accomplished by positioning the cylinders at desiredradial positions to individually adjust the stroke of the pistons.

To allow for individual stroke adjustment of the pistons, each cylinder12 a is pivotally connected at an end 42 a of the cylinder to meteringpump housing 44 a by a pin 46 a. At the opposite end 48 a of thecylinder is a threaded rod 73 a mounted to housing 44 a and a knurlednut 75 a received on rod 73 a. Cylinder 12 a includes an extension 60 awith a through bore 60 b. Extension 60 a is received on rod 73 a withrod 73 a extending through bore 60 b. As oriented in FIG. 63, nut 75 ais positioned on rod 73 a above extension 60 a, and a spring 62 a ispositioned about rod 73 a below extension 60 a. Spring 62 a acts betweenhousing 4 a and extension 60 a to bias extension 60 a toward nut 75 a.

Turning nut 75 a lowers or raises extension 60 a, causing cylinder 12 ato move about pivot pin 46 a, bringing cylinder 12 a closer or furtherfrom central pivot 40 a. Since the angular swing of transition arm 24 ais a constant, determined by the angular offset of arm 34 a, adjustingthe distance of cylinder 12 a from central pivot 40 a adjusts thestroke, which then remains constant. Thus, turning nut 75 a to lower nut75 a on rod 73 a slides extension 60 a down rod 73 a with cylinder 12 apivoting about pin 46 a. This adjusts the position of piston 16 a alongarm 30 a to reduce the stroke of piston 16 a, and thus reduce the volumeof pumped fluid. Turning nut 75 a to raise nut 75 a on rod 73 a slidesextension 60 a up rod 73 a with cylinder 12 a pivoting about pin 46 a,increasing the stroke of piston 16 a, and thus increasing the volume ofpumped fluid. Extension bore 60 b has a larger diameter than thediameter of rod 73 a to provide a clearance that accommodates the radialmovement of extension 60 b about pin 46 a The stroke of each piston 16 ain metering pump 10 a can be independently adjusted by turning therespective nut 75 a.

The length of drive arm 30 a determines the amount of stroke adjustmentthat is possible by changing distance, D. The length of drive arm 30 acan be up to about three times the stoke length since the loads seenduring metering are relatively small. In addition, the variable strokemechanisms described above can be employed to permit the output to bevaried over a wide range, while still maintaining the same proportionsin the mix.

Metering pump 10 a advantageously locks the fluid proportions to exactand repeatable values. A cylinder can be separately removed and replacedby one of a different diameter. The speeds and loads for the mixingoperation are low enough to permit oil-less operations, and thus, acleaner operating metering pump. Metering pump 10 a is also applicableto applications where one fluid is being delivered, or various fluidsare being mixed at equal proportions.

Referring to FIG. 65, a linear generator or motor 210 includes one ormore piston assemblies 212 mounted circumferentially about a transitionarm 214. Transition arm 214 is mounted to a universal joint 216, anddrive pins 218 couple transition arm 214 to piston assemblies 212 viapiston joint assemblies 220. Transition arm 214 is also coupled to aflywheel 222. When functioning as a generator, rotation of flywheel 222causes motion of piston assemblies 212 that is linear in space andsinusoidal in time (i.e., simple harmonic motion). When functioning as amotor, the motion of piston assemblies 212 causes rotation of flywheel222.

Each piston assembly 212 terminates in a permanent magnet 230 thatreciprocates with the piston assembly. Each piston assembly 212 ishoused within a non-magnetic cylinder 232 having a coil 234 locatedwithin the cylinder wall 236. Coil 234 is wound circumferentially aboutmagnet 230. Rotation of flywheel 222 causes reciprocating, linear motionof magnet 230 such that alternating current is produced at coil 234 atthe revolving frequency of flywheel 222. The waveform is adjustable bychanging the shape of the coil and/or the magnetic field.

With three 120° spaced cylinders the alternating current produced isthree-phase. Since the motion of magnet 230 is linear in space andsinusoidal in time and the voltage produced is proportion to the speedof the magnet, with three 120° spaced cylinders a coil winding having auniform number of turns per inch produces a sinusoidal voltage output aslong as the magnet remains within the coil during the reciprocatingmotion.

As a linear generator, rotation of flywheel 222 causes linear motion ofpiston assemblies 212 to generate power. As a linear motor, applying acpower to coil 234 causes piston assemblies 212 to reciprocate, whichcauses flywheel 222 to rotate. This is accomplished with no brushes orcommutators.

Piston assemblies 212 can be single-ended or double-ended pistons.Magnet 230 and coil 234 can be positioned on one or both sides of adouble-ended piston. Coil 234 can be inside or outside magnet 230, orboth. For example, referring to FIG. 66, piston assembly 212 aterminates in a magnetic tube 240 having a tubular portion 241magnetized at right angles to the axis. Cylinder 232 a includes aninner, cylindrical coil 242 positioned within tube 240 and an outer,cylindrical coil 244 positioned around the outside of tube 240. Coils242, 244 are surrounded by transformer laminations 246. Magnetic tube240 oscillates within coils 242, 244 driven by motion of piston assembly212 a, producing a sinusoidal voltage output. For a coil and laminationlength of L and a gap width of d, the tube oscillates over a strokedistance (L-d)/2, and the tube is of length (L+d)/2. The length of thetube and the stroke can be adjusted to perfect the sinusoidal waveform.

Referring again to FIG. 65, in a hybrid generator configuration, oneside 250 a of a double-ended piston assembly 212 functions as a gasolineengine, and the other side 250 b generates ac power. In a hybrid pump orcompressor configuration, side 250 b is a motor with ac power applied tocoil 230 causing piston assembly 212 to reciprocate, and side 250 afunctions as a pump or compressor. In the hybrid configurations, thedirect push from power to load along the line between two opposing endsof the piston assembly increases efficiency by eliminating rotatingfriction in the power path, and largely eliminates forces that need tobe passed through the drive pins 218, transition arm 214, and universaljoint 216. The drive pins 218, transition arm 214, and universal joint216 do very little work, i.e., just synchronizing the pistons, andtherefore can be made very light. The coil and magnet of FIG. 66 canalso be used in the hybrid configurations.

Referring to FIG. 67, a compressor or pump assembly 260 includes adouble-ended piston assembly 262 and a single-ended piston assembly 264.Connected to a piston rod 266 of piston assembly 262 opposite pistonhead 268 is a linear electromagnetic motor 270, such as described above.The single motor 270 can drive both piston assemblies 262, 264 becausemotor 270 can both push and pull piston assembly 262. When motor 270 isdriving to the right, as viewed in FIG. 67, the force is transferreddirectly from motor 270 to piston head 268, and thus to the load. Pistonhead 268 is driven to the right, and the motion of piston rod 266 istransferred by transition arm 272 to piston assembly 264, moving pistonhead 274 of piston assembly 264 to the left for an intake stroke. Whenmotor 270 is driven to the left, the force is transferred directly topiston head 268, moving piston head 268 to the left for an intakestroke. Again, the motion of piston rod 266 is transferred by transitionarm 272 to piston assembly 264, now moving piston head 274 to the right,and thus to the load.

The forces applied to piston assemblies 262, 264 are not transmittedthrough nose pin 280, flywheel 282, or drive shaft 284. The nose pin,flywheel, and drive shaft simply act to keep the motions of the pistonssynchronized and sinusoidal. The assembly is efficient due to the highefficiency of motor 270, typically over 90%, and the direct transfer ofload from motor 270 to piston assemblies 262, 264 through the transitionarm acting as an efficient rocker arm.

Assembly 260 can be balanced, generally as described above. Inparticular, assembly 260 includes five counterweights 300 a′, 302 a, 304a, and two not shown coupled to the transition arm with one positionedabove the plane of the paper in FIG. 67, and one below the plane of thepaper, such as counterweights 1160, 1162 shown in FIG. 45. Counterweight300 a′ acts to equalize the weight of piston assemblies 262, 264, i.e.,accounts for the added weight to piston assembly 262 from the magnet 290of motor 270 and any extra length of piston rod 266. For a two pistonassembly flat configuration, counterweights 302 a, 304 a create a rotarycouple equal in magnitude and 180 degrees out of phase to the rotarycouple of the piston assemblies and counterweights 1160, 1162 about thecenter, C, of universal joint 310 a.

The hybrid generator can be used to drive the wheels of a vehiclethrough linear motors at the wheels, particularly three-phase or morelinear motors with rotary shaft output. As the engine speed increases,the frequency of the a-c power produced rises, and thus the speed of thewheels increases synchronously with the generator. Alternatively, ahydraulic three-phase line can connect a hybrid pump to hydraulic motorsat the wheels; or a single high pressure hydraulic line can run from theengine to each wheel, and then a hydraulic motor with valved input andoutput lines transfers power from the engine to the wheels without theneed to be synchronous.

If the position of universal joint 216 is moved to act as a zeroclearance compressor or a variable stroke constant compression ratioengine, as described above, the linear generator or motor is notsensitive to the precise position of the magnet. As the stroke isadjusted for some purpose on the engine side, the other side continuesto function normally. Some overrun on the length of the magnet isrequired. The linear motor is also compatible for use as an integralelectric motor/compressor.

Referring to FIG. 68, often it is useful or necessary to convert acpower from one form to another, i.e., from single-phase 120-volt powerto three-phase 240-volt power, or vice versa The mechanism shown in FIG.68 performs this conversion using the left side of the mechanism forsingle-phase input or output, and the right side for three-phase inputor output. The assembly 3300 includes a double-ended piston assembly3302, and two single-ended piston assemblies 3304 (only one of which canbe seen in the view of FIG. 68) that are spaced apart 120° from thedouble-ended piston assembly. All four pistons (one of which can not beseen in the view of FIG. 68) contain magnetic material 3306, and allfour cylinders have windings for the input and output voltages asfollows: winding 3308 on the left-hand side is wound for 120 volts ac,and three windings 3310 on the right side are wound for 240 volts ac,with the wires sized to support the required current demands.

The application of 120 volts to coil 3308 causes rotation of the shaft284 and counterweight 302 a at a constant synchronous speed equal to theac input frequency, and correspondingly, each of the output coils 3310generates a voltage at the same frequency. The magnitude of thissecondary voltage depends, other things being equal, primarily upon theratio of turns between the input and output coils. In this case thatratio would be 2:1. Each output has the same voltage, but the phaserelationship is in accordance with the relationship in space among thethree coils, i.e., 120° apart, to produce three-phase ac.

The mechanism works as well in reverse to convert three-phase 240-voltac to single-phase 120-volt ac power. The mechanism could also convertbetween other phases by using a different number or configuration ofpiston assemblies.

The output shaft from the flywheel of various embodiments can be used todrive the flywheel of various other embodiments. For example, referringto FIG. 69, gasoline engine pistons 3320 drive air compressor pistons3322, and the output shaft 3324 drives a 120 volt single phase acgenerator 3326, and a 240 volt three phase ac generator 3328.

Referring to FIG. 70, a drive assembly 4100 with overload protectionincludes one or more piston assemblies 4105 mounted circumferentiallyabout a transition arm 4110. Transition arm 4110 is mounted to auniversal joint 4115, and drive pins 4120 couple transition arm 4110 topiston assemblies 4105 via piston joint assemblies 4125, as describedelsewhere in this application. Transition arm 4110 is also coupled to aflywheel 4130 which houses an overload protection mechanism 4135.Flywheel 4130 is coupled to an input drive 4140.

The drive assembly 4100 functions, e.g., as a generator, a compressor, apump, an integral engine compressor, or an integral engine pump. Therotation of the input drive 4140 causes rotation of the flywheel 4130which, in turn, causes the linear motion of the piston assemblies 4105.

An overload is an increase in pressure above an upper limit of theoperating pressure of the drive assembly 4100. Overloads are typicallycaused by downstream blockage restricting flow such that pressure beginsto build at drive assembly 4100. When the pressure rises above an upperlimit of the operating pressure, an overload occurs that may damage thedrive assembly 4100 or components downstream of the drive assembly 4100.An overload can be caused, for example, by a closed flow control valve.

Referring to FIGS. 71 and 72, flywheel 4130 defines a slot 4200.Overload protection mechanism 4135 includes one or more springs 4210(two springs 4210 a, 4210 b being shown in FIG. 72) positioned withinslot 4200, a pad 4215 coupled to springs 4210, a block 4220 alsopositioned within slot 4200 and designed to receive a nose pin 4205 oftransition arm 4110, and an optional shut-off or overload indicatormechanism 4225. Referring also to FIG. 73, slot 4200 is bounded by afirst sidewall 4400, a second sidewall 4405, a third sidewall 4410, andlateral sidewalls 4411 (FIG. 72) that are shaped to guide block 4220during movement of block 4220 in response to an overload and to aid instabilizing block 4220 during normal operation, as discussed below.Third sidewall 4410 includes a flat first portion 4415 for stabilizingblock 4220 during normal operation, a curved second portion 4420 forguiding block 4220 during movement of block 4220 in response to anoverload, and a flat third portion 4425 for stabilizing spring 4210 inits operating position. Referring also to FIG. 71, curved second portion4420 has a radius of curvature R₁ which is the same as the distance D₁(FIG. 73) from a point of contact P₁ of block 4220 with third sidewall4410 (when block 4220 is in its design stroke position during normaloperation) to the center point U of universal joint 4115.

Referring to FIG. 74, block 4220 has a first curved end 4230 a, a secondcurved end 4230 b, and flat sides 4235. Block 4220 also defines a borehole 4231 sized and shaped to receive nose pin 4205 of transition arm4110. Located within bore hole 4231 is, e.g., a sleeve bearing 4232.First curved end 4230 a is cylindrically curved to mate with pad 4215 tostabilize and guide block 4220 during movement of transition arm 4110 inresponse to an overload. In one implementation, first curved end 4230 ahas a radius of curvature that extends from center B of block 4220 tothe point of contact between pad 4215 and block 4220.

Second curved end 4230 b is curved such that torsional loads caused bycontact between block 4220 and sidewall 4405 of slot 4200 when block4220 is in its design stroke position during normal operation areminimized. Torsional loads on block 4220 are undesirable because suchloads increase sideloads between block 4220 and lateral sidewalls 4411of slot 4200. Increased sideloads increase the minimum overload forcenecessary to compress springs 4210 and thus increase the minimumoverload force necessary to actuate overload protection mechanism 4135.

Specifically, second curved end 4230 b is an ellipsoid surface having afirst radius of curvature R₂ which is the same as the distance D₂ (FIG.71) extending from the center B of block 4220 to the point of contact P₂of block 4220 with sidewall 4405. Referring again to FIG. 72, secondcurved end 4230 b also has a second radius of curvature that is designedto be smaller than the radius of curvature of sidewall 4405. Sidewall4405 and second curved end 4230 b shown in FIG. 72 are curved tolocalize the contact of block 4220 and sidewall 4405 to an approximatearea around point P₂.

Referring to FIGS. 71 and 75, springs 4210 abut against first sidewall4400 of slot 4200 and against surface 4254 of pad 4215. Pad 4215includes a cylindrical projection 4255 that is received within one ofsprings 4210 to couple pad 4215 to the spring. Pad 4215 also includes acylindrically curved surface 4216 that engages the first curved end 4230a of block 4220 to stabilize and guide block 4220 during movement oftransition arm 4110 in response to an overload.

Springs 4210 exert a biasing force on block 4220 through pad 4215 tomaintain block 4220, and thus transition arm 4110, in a predeterminedposition during normal operation corresponding to the desired stroke ofthe drive assembly. Block 4220 is stabilized by contact with secondsidewall 4405 and flat first portion 4415.

When an overload occurs, transition arm 4110 through nose pin 4205 actson block 4220, moving block 4220 in the direction of arrow, A (FIG. 71),against the biasing force of springs 4210. Curved second portion 4420 ofslot 4200 guides the movement of block 4220 and is radiused to followthe arced motion of the nose pin 4205. Springs 4210 keep block 4220 incontact with curved second portion 4420 at all times during the block'smovement. Transition arm 4110 thus moves toward a zero stroke positionin which transition arm axis, X, is aligned with drive assembly axis, Y.This decreases the stroke of piston assemblies 4105 causing a decreasein flow that reduces the pressure seen by the drive assembly 4100 andcomponents downstream of the drive assembly 4100. At the same time,flywheel 4130 and input shaft 4140 can continue rotating at theirpreoverload speed, even if the stroke is decreased to zero, thuspreserving the rotational inertia of the flywheel and input shaft.

Referring to FIGS. 76A-76D, in response to an overload caused by adownstream blockage, block 4220 moves, e.g., from the normal operatingposition of FIG. 76A to the zero stroke position of FIG. 76C. A piston4107 in piston assembly 4105 travels a full stroke distance FScorresponding to the distance moved by the piston when the flywheelrotates 180 degrees.

As shown in FIGS. 76C and 76D, when drive assembly 4100 has experiencedan overload due to a downstream blockage 4259 that, e.g., has completelyrestricted the flow from piston assembly 4105, the overload acts ontransition arm 4110 through piston assembly 4105 to completely compresssprings 4210 and thereby position block 4220 at a zero stroke position(i.e., axes X and Y are aligned). When block 4220 moves to the zerostroke position due to the overload, piston 4107 in piston assembly 4105moves a distance D equal to half of the full stroke distance FS. Thismovement is half a stroke and corresponds to a 90 degree rotation offlywheel 4130. If piston assembly 4125 were in the middle of a strokeprior to occurrence of the blockage, rather than having just completedthe stroke, the distance D would be less than half the full strokedistance FS and flywheel 4130 would have rotated less than 90 degrees.

Accordingly, the maximum amount of time that drive assembly 4100 canexperience an overload is a period of time equivalent to the time ittakes for flywheel 4130 to rotate a maximum of 90 degrees (correspondingto movement of transition arm 4110 before the overload acting on thetransition arm is in the direction of arrow, A). This period of time isacceptably short to limit any possible damage before the overloadprotection mechanism reacts to the overload, e.g., for drive assembliesoperating at 3,000 RPM the time period is 5 milliseconds or less, or at1,700 RPM the time period is 8.8 milliseconds or less.

When the cause of the overload is removed or otherwise dissipated,springs 4210 push block 4220 back toward the design stroke position.Overload protection mechanism 4135 thus returns drive assembly 4100 tonormal operation automatically when the overload is removed. The speedto which drive assembly 4100 can return to normal operation is aided bymaintaining the rotational inertia of the flywheel and output shaftduring the overload.

If downstream blockage 4259 only partially restricts the flow frompiston assembly 4105, the pressure gradually builds on drive assembly4100. When the pressure increases above the upper limit of the operatingpressure of drive assembly 4100, block 4220 begins to compress springs4210 resulting in a decrease of the stroke of piston assemblies 4105.The stroke of the piston assemblies 4105 decreases until the flow fromthe piston assemblies 4105 matches the reduced flow permissible throughthe blockage. This decrease in stroke of the piston assemblies 4105limits any further increase in pressure seen by the drive assembly 4100and any downstream components.

The biasing load applied by spring 4210, and thus the force needed tocompress springs 4210 in response to an overload, is selected based uponthe application or use of drive assembly 4100. Typically, springs 4210are designed to compress in response to an overload force that is 1.1 to1.5 times the force needed to maintain block 4220 in the normaloperation position. For example, a water pump drive assembly that iscapable of 3500 psi of output, during normal operation, exerts a forceon spring 4210 in the direction of arrow, A, of approximately 835 lbs.Springs 4210 are selected to compress, e.g., in response to a force of919 lbs (i.e., 1.1 times the normal operating force on springs 4210).

Alternatively, springs 4210 are designed to compress in response to asignificant overload (i.e., 2 or 3 times the normal operating load). Anyload above the normal operating load that is not reduced by compressionof springs 4210 is seen by drive assembly 4100 and its downstreamcomponents. The amount of load above the normal operating load that canbe tolerated before reduction by compression of springs 4210 depends onthe ability of drive assembly 4100 and the downstream components tohandle the incremental extra load above the normal operating load.Springs 4210, therefore, are chosen based on the load bearing ability ofdrive assembly 4100 and the components downstream to drive assembly4100.

Referring to FIGS. 71-73, when an overload occurs, an optional shut-offor overload indicator mechanism 4225 turns on a light indicator (notshown) to inform the user of the drive assembly that an overload hasoccurred, and alternatively or additionally shuts off the operation ofpiston or pump assemblies 4105 by, for example, turning off the power toinput drive 4140. Mechanism 4225 includes a switch 4245 and a pin 4240attached to pad 4215 for activating switch 4245. Pin 4240 extendsthrough spring 4210 a toward switch 4245. When block 4220 moves downwardin response to an overload, pin 4240 extends through a hole 4250 infirst sidewall 4400 to make contact with switch 4245 to activate theswitch producing a signal that automatically shuts off the operation ofthe piston or pump assemblies 4105 or alternatively or additionallyactivates a light indicator (not shown) that informs the user of thedrive assembly that an overload has occurred. When the overload isremoved, block 4220 moves back to its original position and pin 4240breaks contact with switch 4245. The light indicator is then deactivatedand drive assembly 4100 returns to normal operation.

Springs 4210 are, for example, coil springs as shown in FIGS. 70-72. Thecoil springs can be replaced by any other mechanism selected to exertthe force needed to hold block 4220 in slot 4200 and keep transition arm4110 in its normal operating position during normal loading andoperation, and to allow block 4220 to move to a zero stroke positionduring an overload. For example, referring to FIGS. 77 and 78, anoverload protection mechanism 4500 includes a leaf spring 4515 locatedwithin a slot 4505 defined by a flywheel 4510. Spring 4515 is attachedto a spring retainer plate 4520 and extends from the spring retainerplate into slot 4505 where a connecting plate 4518 attached to spring4515 contacts a block 4525 to bias the block toward its operatingposition, as described above.

Referring to FIG. 79, leaf spring 4515 is clamped between springretainer plate 4520 and flywheel 4510. Alignment of flywheel 4510, leafspring 4515, and spring retainer plate 4520 can be facilitated by theuse of alignment dowels 4545. Flywheel 4510, leaf spring 4515, andspring retainer plate 4520 each define screw or bolt holes 4511, 4516,and 4521, respectively, to receive screws or bolts 4540, and each definedowel holes 4512, 4517, and 4522, respectively, to receive alignmentdowels 4545. Connector plate 4518 is attached to leaf spring 4515 by,for example, bolts. Leaf spring 4515 and connector plate 4518 togetherdefine a hole 4519 sized and shaped to receive the transition arm 4110.Spring retainer plate 4520 defines a hole 4523 sized and shaped toreceive the transition arm 4110.

Referring to FIG. 80, slot 4505 has the same shape as slot 4200described above, except that sidewall 4710 need not include portion 4425and sidewall 4705 is extended (FIG. 73). Block 4525 is the same as block4220 described above.

Referring to FIG. 81, an overload protection mechanism 4840 for use inan assembly having variable stroke, e.g., a variable stroke pumpassembly 4800, includes one or more piston assemblies 4805 mountedcircumferentially about a transition arm 4810. Transition arm 4810 ismounted to a universal joint 4815, and drive pins 4820 couple transitionarm 4810 to piston assemblies 4805 via piston joint assemblies 4825.Transition arm 4810 is coupled to a flywheel 4845 with a variable strokeclearance mechanism 4830. Variable stroke clearance mechanism 4830 isactuated by a control rod 4835, as described previously in reference toFIG. 54. Overload protection mechanism 4840 is mounted to control rod4835.

Referring to FIG. 82, overload protection mechanism 4840 includes ahousing 4900 defining chambers 4901, 4902, and a rod 4903 located inchamber 4902 and fixed to housing 4900 at end 4912. Control rod 4835 isreceived in chamber 4901 and coupled to housing 4900 by a bearing 4904such that rotation of rod 4835 does not cause corresponding rotation ofoverload protection mechanism 4840. Located within chamber 4902 is aspring 4905 received over rod 4903, a coupler 4906 defining an overloadstroke region 4907, and a control rod extension 4908. Control rodextension 4908 is attached to coupler 4906 by a pin 4909, and is actedupon by, e.g., a hydraulic cylinder 4910. Hydraulic cylinder 4910 can becoupled to the control rod extension 4908 by, e.g., a self-aligning,non-rotating, coupling (not shown). Housing 4900 is axially movablerelative to coupler 4906 and control rod extension 4908.

During normal operation, to change the stroke of piston assemblies 4805,hydraulic cylinder 4910 is actuated to move rod 4908 axially. The motionof rod 4908 is transferred to rod 4835 through housing 4900. Inparticular, when rod 4908 is moved in the direction of arrow, B, themotion of rod 4908 is transferred to coupler 4906, then through spring4905 (which is not compressed under normal load conditions) to housing4900, and then to rod 4835 through bearing 4904. When rod 4908 is movedin the direction of arrow, C, the motion is transferred to coupler 4906,then by contact of the coupler with the housing at surface 4911, throughhousing 4900 to rod 4835 via bearing 4904. The spring constant is chosensuch that the spring does not compress under normal load conditions forthe maximum stroke position (which is the stroke position at which thehighest normal load condition is seen).

When the variable stroke pump assembly 4800 experiences an overload, themovement of transition arm 4810 in response to the overload acts to pushcontrol rod 4835 in the direction of arrow, C, thus also pushing housing4900 in the direction of the arrow, C. However, the axial position ofrod 4908 and coupler 4906 does not change because of the coupling of rod4908 to hydraulic cylinder 4910. The movement of cylindrical housing4900 compresses spring 4905 and causes rod 4903 to enter overload strokeregion 4907 such that when an overload is experienced, the stroke of thepiston assemblies decreases limiting the possibility of jamming andbreakage while allowing the flywheel 4845 and the control rod 4835 tocontinue rotating. Once the overload is relieved (e.g., by removal of ablockage downstream of the piston assemblies), the piston assembliesautomatically return to their full stroke position. The length, x, ofoverload stroke region 4907 is selected to accommodate changes in strokefrom maximum stroke to zero stroke.

The piston assemblies 4105 can include, e.g., a sealed member forcompressing or pumping gases or an unsealed plunger typically used forpumping liquids.

Other embodiments are within the scope of the following claims.

For example, the double-ended pistons of the forgoing embodiments can bereplaced with single-ended pistons having a piston at one end of thecylinder and a guide rod at the opposite end of the cylinder, such asthe single-ended pistons shown in FIG. 32 where element 604, rather thanbeing a pump piston acts as a guide rod.

The various counterbalance techniques, variable-stroke and/orcompression embodiments, and piston to transition arm couplings can beintegrated in a single engine, pump, compressor, generator, or motor,and can be used in the various embodiments of engines, pumps,compressors, generators, and motors described above.

1. An assembly, comprising: at least one piston assembly; a rotatingmember; a transition arm coupling the piston assembly to the rotatingmember; and an overload protection mechanism coupled to the transitionarm and configured to reduce piston stroke of the piston assembly uponapplication of an overload to the assembly while enabling the rotatingmember to continue rotating.
 2. The assembly of claim 1 wherein therotating member comprises a flywheel and the transition arm and theoverload protection mechanism are coupled within the flywheel.
 3. Theassembly of claim 1 further comprising a control rod for adjustingoperating piston stroke of the piston assembly, the overload protectionmechanism being coupled to the transition arm by the control rod.
 4. Theassembly of claim 1 wherein the overload protection mechanism isconfigured to reduce piston stroke of the piston assembly while enablingthe rotating member to continue rotating at a substantially pre-overloadspeed.
 5. The assembly of claim 1 wherein the overload protectionmechanism is configured to reduce piston stroke of the piston assemblyto zero.
 6. The assembly of claim 1 wherein the rotating member definesa slot and the overload protection mechanism includes at least onespring positioned in the slot and configured to bias the transition armtowards an operating stroke position.
 7. The assembly of claim 6 whereinthe slot is bounded by a plurality of different surfaces sized andshaped to guide the transition arm from an operating stroke position toa reduced stroke position upon application of the overload.
 8. Theassembly of claim 6 wherein the spring comprises a coil spring.
 9. Theassembly of claim 6 wherein the spring comprises a leaf spring.
 10. Theassembly of claim 1 further comprising a control rod for adjusting theoperating stroke of the piston assembly.
 11. The assembly of claim 10wherein the overload protection mechanism is coupled to the control rod.12. The assembly of claim 11 wherein the overload protection mechanismincludes a spring and a control rod extension coupled to the spring. 13.The assembly of claim 12 further comprising a hydraulic cylinder coupledto the control rod extension.
 14. The assembly of claim 13 wherein thespring has a spring force selected such that application of a load onthe control rod extension by the hydraulic cylinder to adjust pistonstroke is transferred to the control rod by the spring, and applicationof an overload to the spring by the control rod causes the spring tocompress to allow a decrease in piston stroke.
 15. The assembly of claim1 wherein the overload protection mechanism is configured to increasepiston stroke upon removal of the overload.
 16. The assembly of claim 1further comprising at least three piston assemblies, the transition armcoupling each piston assembly to the rotating member.
 17. An overloadprotection mechanism for protecting an assembly from damage due to anoverload, the assembly including at least one piston assembly and atransition arm coupled to the piston assembly, the overload protectionmechanism comprising: a biasing member configured and arranged to biasthe transition arm towards an operating stroke position, and react inresponse to application of an overload such that the position of thetransition arm is adjusted to reduce piston stroke of the pistonassembly.
 18. An overload protection mechanism for protecting anassembly from damage due to an overload, the assembly including at leastone piston assembly and a control rod for adjusting operating stroke ofthe piston assembly, the overload protection mechanism comprising: acontrol rod extension configured to receive a load for adjusting theoperating stroke of the piston assembly, and a spring acting between thecontrol rod and the control rod extension, the spring having a springforce selected such that application of the load on the control rodextension to adjust piston stroke is transferred to the control rod bythe spring, and application of an overload to the spring by the controlrod causes the spring to compress to allow a decrease in piston stroke.19. A method of protecting an assembly from an overload, comprising:reducing piston stroke upon application of an overload to the assemblywhile enabling a rotating member to continue rotating at a substantiallypre-overload speed.
 20. The method of claim 19 wherein reducing pistonstroke upon application of an overload comprises reducing piston stroketo zero.
 21. An assembly, comprising: at least one piston assembly; arotating member; a transition arm coupling the piston assembly to therotating member; and means for reducing piston stroke of the pistonassembly upon application of an overload to the assembly while enablingthe rotating member to continue rotating.